Is Climate Change, Migration and Health Related to Each Other?

social science, global health, migration

Climate change, recently the climate crisis has been highlighted due to the impacts of climate change and air emissions on health and human wellbeing. The consequences are not only facing the health and wellbeing, but also facing the ecological, political, and societal crises. Climate change only made its way into the world’s focus in the early 2000s, even though scientists knew about it as early as the 1980s. Such a global threat is affecting the global in different ways and mechanisms. It is important to understand these ways and mechanisms because these will affect the human’s behaver and decision making in different ways. According to Watts, Adger, Agnolucci, Blackstock, Byass, and Cai, (2015), when temperature increases by global warming, the global health will be affected by direct and indirect mechanisms, which will interact with the social dynamics to produce the health outcomes. That means the direct risks will include increased heat stress, floods, and drought, as well as increased frequency of intense storms. The indirect risks will mediate through changes in the biosphere which can also lead to negative health effects.


Climate change can be translated to many forms of environmental and health degradations including, rising sea levels, hurricanes, water scarcity, reduced rainfall in drylands, and all these could be later translated to health issues and migration. All these effects will have an impact on global health, and global patterns of migration in multiple ways. The effects will have different pathways and mechanisms, and all these pathways and mechanisms will contribute to defining human health and behavior, as well as decision making. Usually, the extreme rainfall events translate into floods. Furthermore, the regions of large population growth are most exposed to the flood risk, especially in sub-Saharan Africa and South Asia. The same storm and floods could affect also the migration pattern in indirect ways, for example when the water quality is degreasing by the storm and floods, then, infection disease will be spreading and that may lead to emigration. Also, when land use is changing by floods and when more ecological changes occur, then all these could lead to emigration either in an indirect way or by the health impact that will happen by the social dynamics, which could be affected by direct and indirect ways. The social dynamics are such: poor health status, socioeconomic status, and public health infrastructure. The health impact may look like allergies, respiratory disease, cardiovascular disease, injures, poisoning, undernutrition, mental illness, and infectious disease. (Watts et al. 2015); (Ridde, Benmarhnia, Bonnet, Bottger, Cloos, & Dagenais, 2019).


Mahmooei, and Parris (2012), stated that Bangladesh is one of the most countries which is vulnerable to climate change impacts such as extreme weather events. Also, as a result of climate change in Bangladesh, the migration dynamics will be increased in the coming years. Furthermore, Watts et al. (2015) stated that the risks related to water shortages and flood are involving large populations, the author warned that “an additional 50 million people and 30 000 km² of land could be affected by coastal storm surges in 2100, with attendant risks of direct deaths and of infectious diseases” (P. 1873). This essay will identify and demonstrates more knowledge and examples about the mechanisms and pathways of the effect of climate change on health and migration as well as how these are related to each other.


Research question

Is climate change, migration and health are related to each other?


The mechanisms and pathways

First, it is important to demonstrate the first category of air emissions that are contributing to global climate change, to understand the case. The air emissions are releasing gases, such Nitrous Oxide with the formula (N₂O), this is an oxide of nitrogen. Also, a well-known gas with his damage to the ozone layer called hydrochlorofluorocarbons with the formula (HFC). As well as the Hydrocarbon with the formula (CH₄) and Carbon Dioxide with the formula (CO2). All these gases are contributing to global climate change by increasing the temperature, heatwaves, and extreme weather, as well as by precipitation variation. The direct effects of climate change are including increased heat stress, floods, drought, and increased frequency of intense storms (Watts et al. 2015).


The direct effect of climate change on health are mediated by frequency, intensity, and duration. When these consequences increase, then the migration will also increase. There has been evidence, that people have migrated to other places. According to UNHCR, (2014); WHO, (2019) Over 1 billion migrants worldwide have emigrated, 258 million international, and 763 million internal. That could be a sign of climate change, because for instance, the storms and floods, will not only lead to health-related issues, such as mental health problems, poor health, shortage in food, and clean water but also will lead to displacement and migration. That because when people are losing their houses or farms, due same floods, and storms, then, they will be forced to emigrate to another place to have a safer environment and houses as well as food availability. Watts et al. (2015) stated that risks related to water shortages and flood are involving large populations. The author warned that “an additional 50 million people and 30 000 km² of land could be affected by coastal storm surges in 2100, with attendant risks of direct deaths and infectious diseases” (P. 1873).


That could be true, for example, when drought and water scarcity dominate the region and when extreme weather events happen and when land degradation and desertification occur, and when the sea levels are rising. Then, as a result, food scarcity will occur, and emigration will increase. People will search for new resources. Also, armed conflicts will increase, which also will lead to migration and mental health problems such as traumatic stress disorder, depression, anxiety, and suicides as well as health inequity (Michael 2013); (Cunsolo & Ellis 2018).


What matters in such cases, is the population vulnerability to the exposure, sensitivity, adaption, and capacity, as well as the prespecified preventative policies that should be addressed by the states, because that will moderate and modify the outcome. In these cases, does gender and age differences matter? Who is more sensitive to climate change? Who can adapt to climate change? Regarding gender and floods related deaths. The gender inequality could interact with the exposure differently. For instance, according to Watts et al. (2015), in high-income countries, flood-related deaths are more common in the male population, while in low-income countries, women and girls are disproportionately affected.


The question here: Is that true? According to UNHCR, (2014); WHO, (2019), almost half of all international migrants are women and girls. So, women and girls are more affected by disasters, especially in low-income countries. Nevertheless, women in low-income countries have fewer resources and power than men, they tend to emigrate. That means the women can’t tolerate the disasters in low-income countries. That’s why they will have one option to choose between. Either to choose death or emigration. In high-income countries the gender inequality is less, that’s why women can survive because women might have resources and power to survive during the disasters. For example, if the floods come and the women have a car, she can run with her children fast from the place. While in low-income countries when a woman has no car, she can’t run away from the floods. What is proving this example, is that it has been stated, that the risks will affect mostly poor and marginalized groups, as well as people with disabilities, elderly, and young children (Watts et al. 2015); (Watts, Amann, Ayeb-Karlsson, Belesova, Bouley, Boykoff, 2018); (UNHCR, 2014); (WHO, 2019).


According to Watts et al. (2015), there is no evidence that climate change has increased the risk of violence, civil conflict, or war between states. That could be justified for their wars and reasons for concern. But when the climate change leads to conflict, then the conflict will lead to emigration and health inequity, because when drought and water scarcity, land degradation and desertification occur, then that may lead to food scarcity and then to emigration, because people will search for new resources. People who couldn’t emigrate may start armed conflicts or long-term conflict, while that may increase the mental health problem, such as traumatic stress disorder, depression, and anxiety (Michael 2013); (Cunsolo & Ellis 2018).


According to WHO (2019), the increase in temperature and the change in rainfall patterns indicate an increased risk for borne diseases such as malaria, dengue fever, and Lyme disease. Usually, when such a disaster happens, people tend to run or emigrate from the region that has been infected. That because when transmission infection disease covers a region, that may affect the health status and limit mobility. These effects will lead also to many health effects for example when the temperature will rise, and the weather gets extreme and borne disease such as malaria occurred an x person emigrated from the infected region to another country. The X person will be an immigrant in x country, there he or she may be exposed to racism, stigma, and discrimination or exacerbates marginalization, disempowerment, or social exclusion. Then the immigrant x will have negative health effects and then it will be related to mortality and morbidity. (Grove & Zwi, 2006); (Viruell-Fuentes, Miranda, & Abdulrahim, 2012).


Furthermore, Watts et al. (2015), stated that when the sea level rises due to climate change. That can lead to regional changes and loss in biodiversity. That can threaten the population’s health through air pollution, disease, food insecurity, and displacement. Why sea level matter? Often, the coastal communities are suffering more from coastal flood risk, and usually, people tend to live with high density in coastal areas. For instance, in the United States, around 40 percent of the population lives in high population-density coastal areas and any coastal flood will threaten the population’s life and that may cause inboard or outboard migration. Lindsey (2019).


Not only the storms, floods, drought, and heat will affect global health, and global patterns of migration, but also the air emissions that cause pollution. According to CCAC. (2018). world health organization stated that around 90% of the world population breathes polluted air. Moreover, indoor and outdoor air pollution causes death to around 7 million people per year. Most of them are from low- and middle-income countries. If we considered well, then we would understand that the air emission is more dangerous for global health than only the effect of storms, floods, drought, and heat.

climate change, migration, social science, global health,

Demonstrating the second category of the air emissions that are lowering the local air quality. The air emissions are releasing many dangerous particulates, compounds, and gases such Sulphur Dioxide with formula (SO₂) and Ozone with formula (O3) as well as Nitrogen Dioxide with formula (NO2) and some particulates such as PM10 and PM2.5. Even some chemical compounds such Benzene with the formula (C₆H₆). The exposure to these, either outdoor air or indoor air may cause cardiorespiratory disease, acute respiratory infection, cardiovascular disease, lung cancer, stroke, and mental health problem (Watts et al. 2015); (National Pollutant Inventory, 2019).


This category of gases is very dangerous to human been. The awareness has already been in many agencies in different countries for example, in United States the environmental protection agency (2019) stated that (O3) can damage the lungs, cause chest pain, coughing, shortness of breath, inflammation of lung tissue, susceptibility to respiratory infection and throat irritation. Also, the agency for toxic substances and disease registry (2015) stated that the effect of Benzene is determined by the length of time of the exposure and by the amount. A study conducted on workers employed in industries, there they have been exposed to Benzene in workplace air for long term. The result indicated that the exposure to very high levels of benzene in air for 10 minutes can result to death. The exposure to lower levels of benzene in air for 10 minutes can result to drowsiness, dizziness, rapid heart rate, tremors, confusion, headaches, and unconsciousness. Even they stated that eating foods or drinking liquids containing high levels of Benzene can result to irritation of the stomach, vomiting, dizziness, convulsions, sleepiness, rapid heart rate, coma, and death. Moreover, if Benzene meet the eyes it may cause general irritation and damage to the cornea.


Benzene can cause many problems in the blood. For instance, People who breathe benzene for long periods may experience some harmful effects in the tissues that form blood cells. Mostly in the bone marrow and as a result that could disrupt the normal blood production and after that anemia may occur. Furthermore, the long-term exposure can cause Leukemia. Leukemia is a condition when the blood forming organs are defected by cancer. Even the excessive exposure may harm the immune system, which could increase the risk for infection and in most cases can lower the body’s defence against cancer. The exposure to Benzene can affect the fertility among women. the study has shown that women who were breathing high levels of Benzene had irregular menstrual periods. Also, Benzene affect the prenatal development such delaying the bone formation and damaging the bone marrow of the fetus which can result in low birthweight (Agency for toxic substances & disease registry, 2015).


Even the government in Australia has published on her website in the department of the environment and energy, that the national pollutant inventory (2019) stated that, the air emissions will be diffused by airborne particles. The air will carry particulate from Industry sources such as particulate matter PM10 and PM2.5. These particulates can be drawn deep into the lungs through nose or mouth. Recent epidemiological research suggests that there are many negative health effects from these particulates include: fibrosis, cancer, irritation of mucous membranes, toxic effects by absorption of the toxic material into the blood and increased respiratory symptoms, aggravation of asthma and premature death.


Finally, last but not least, the third category is also contributing to climate change. For instance, when the solid discharge such as radioactive materials and water, as well as ash and sulphur affect an area then, these will lead to local contamination which can have different negative health effects, such as acute radiation sickness, cancer, drowning, physical injury and mental health problem, which later also could lead to emigration (Watts et al. 2015).



Climate change, health and migration are related to each other and the relation depends on the intensity and the duration of the climate change. As well as the prespecified preventative policies and population vulnerability to the exposure. Climate change can be translated to many forms of risks and that will play a big role in forced displacement of people in the coming years. Furthermore, the displacement will have negative effects on health and could be a cause of borne disease and poverty. In order to lower the effects of climate change, these forms and hazards should be incorporated into health planning and policy measures, which must include deep cuts in greenhouse gas emissions, efforts to remove CO2 from the atmosphere, protection and enhancement of the biosphere.


8 Comments Physiology FactsPsychology FactsPublic Health

Seasonal Depression, Symptoms, Causes and Treatment

Circadian rhythm, psychology, social-science, Seasonal Depression, Symptoms, Causes and Treatment,

Seasonal Depression 


Depression is dominating the northern part of Europe and the USA and the whole of Canada, in the winter. The seasonal affective disorder is a condition in which individuals experience recurrent depression during the fall/winter. In some places like in the United States, Canada, Norway, Finland, and Sweden, will observe daylight saving time. Shorter days, less sunlight, and darkness. Many kinds of research indicate that daylight saving time can increase the symptoms of seasonal depression for some people. Even more, the research has gone far away from depression to find the available evidence about the existence of an association between daylight saving time and an increase in the occurrence of acute myocardial infarction. According to Manfredini, et. al


Seasonal Depression Includes Symptoms Such as:

Feeling sad or depressed.

losing interest in things previously enjoyed.

People eat more carbohydrates in order to get more dopamine.

long sleep deprivation,

you may sleep only short intervals

Lacking motivation or feeling tired.

Feeling either restless or slowed down.

Feeling guilty due to the feeling that you deserve better options.

Feeling worthless.

Some people have problems with making decisions or concentrating.

Some people who have no options will think about death or suicide.


Internal clock, and melatonin hormone

health, Psychology Topics,

Our bodies are dominated by an internal clock, and melatonin hormone. When sunlight come, the light enters our eyes then it sends the message to our brains that it’s time to wake up and when it’s dark, a hormonal signal is sent to our brains that it’s time to sleep.



What Causes Seasonal Depression?

Circadian misalignment, environmental conditions and sleeping deprivation. Our body clock may become disrupted due to a lack of exposure to sunlight. According to Manfredini, et. al Circadian rhythm is “driven by either central or peripheral clocks. The central circadian clock (called ‘master clock’) is located within the suprachiasmatic nucleus (SCN) of the hypothalamus and accounts for approximately 20,000 neurons”.  Circadian clocks regulate our metabolism and organs, including the heart, skeletal muscle, liver, and adipose tissue. The central clock and the peripheral clocks influence numerous functions, including sleep/rest and endocrine activity as well as the metabolism, autonomic and sympathetic activity. All these can lead to the symptoms we know as seasonal depression.

psychology, social science, anxiety

Treatments For Seasonal Depression

There are Behavioral, medical and nutritional therapy as well as light therapy and psychotherapy. Behavioral therapy starts with involving people with social activities. There is also some medications but we will not make any promotion for any in this article, Even light therapy could help some people, but the most important is the nutritional diet, fore instance you should eat food rich in vitamin D3 or take  vitamin D3 supplement. As well as there is a specific diet for that season.



Moreover, the Cardiovascular system has biological clocks too as well. In fact, biological clocks have been found in the heart, at the cardiomyocyte level but we will not extend to that in this article, so we don’t confuse you more. In our next article we will talk about the cardiomyocyte circadian clock and how all these clocks lead to an increase of occurrence of acute myocardial infarction and which diet you should eat during winter in order to avoid the myocardial infraction. 

3 Comments Physiology FactsPsychology Facts

Social Stratification and Health Inequality- Stress and Depression

Treating Stress, psychology, social science, Social Stratification and Health Inequality- Stress and Depression

Stress! Stressful life events have been linked to heart disease, diabetes, cancers, stroke, fetal death during pregnancy, low birth weight in offspring, and major depression. Stress and stress management affect health. What did it look like in the past? What has changed? How does stress affect you? Where did stress come from? How to change this? This’s what our article about.

This article is a part of our Magazine social stratification and health inequality. Here we will teach you a part of the best diet to reduce the stress and how socioeconomic status during the life course affects your health. We will also argue about the theories that have been used in this discipline in order to determine the causes of stress and diseases. Moreover, how social stratification and health inequality lead to stress and diseases.



Where stress comes from and what it does to your body?

psychology, social science, anxiety, Psychology TopicsNot only the poor people who have stress but also rich people. Everybody is susceptible to stress and diseases. So being poor is not the only reason for stress and diseases. Stress is a response to a mental and physical reaction. Stress be a physical reaction due to hormones included in such as cortisol, adrenaline, and norepinephrine, all those hormones increase breathing and pulse and increase blood flow in the muscles. These symptoms interact directly with the brain function, from the material substances and from the stored information during the life course. Short-term stress can be positive sometimes, such as being stressed to catch the bus and it can have negative effects on health if it becomes long-lasting.


How do you know if you have stress?

  1. You become easily annoyed and impatient about small things

  2. You will feel stiff, tense and your body aches

  3. You will feel abandoned and tired, and therefore you will avoid the social contacts

  4. You will lose your desire for sex and may lose erection

  5. You get infections easier and more often

  6. You feel that time is not enough and therefore you increase the tempo further

  7. You opt out of rest, leisure activities, entertainment and contact with family and friends due to lack of time

  8. A mother more often experiences their child as irksome and that can give negative feelings towards the infant or child.

  9. You get stomach aches, tension headaches or palpitations

  10. You feel it harder to breathe properly

  11. The heartbeat becomes irregular

  12. Heartbeat may be hard to detect

Circadian rhythm, psychology, social-science, Psychology Topics

Stress nowadays

Today, young people are feeling worse than before. Today, teens suffer from psychosomatic disorders. Today, stress is twice as great. Today we have more stress than before due to globalization. Today, everything must be quickly and accurately. Today stress is rising due to the use of the Internet, especially due to social media, such as Instagram and Facebook. Teens start to compare their Capabilities or themselves with others which in some cases can lead to stress and depression. And even suicide. The most causative for stress and disease is the inequalities, especially health inequalities.


Stress in the past

To compare with 1985, where 57% of teenage girls suffer from psychosomatic disorders. In addition, this curve rises proportionally, and there is no specific reason why the stress is rising, but some studies show that it has and does to do mostly with unemployment. Some other studies show that socioeconomic status (SES) is the most causative for stress and diseases. Let’s discover what the science knows about the exposers and the outcomes related to health inequalities.

Why people go to the rail, Social Stratification and Health Inequality, Psychology Topics Stress and Depression

Why people go to the rail

Both the theory of social conditions as fundamental causes of disease and the theory of education learned effectiveness and health may be used to explain health inequalities. We will also first describe the two theories, and then we will compare and contrast them. Second, discuss the strengths and limitations of each of these theories.


The theory of social conditions as fundamental causes of disease

Link and Phelan (1995, pp. 80, 87) emphasis on individually-based risk factors, because there are two concepts, the first one is the social factors or social condition such as socioeconomic status (SES) and social support are fundamental causes of disease. The second is contextualizing of the risk factors by understanding what put people at risk of the risks and how people come to be exposed to the individually-based risk factor. The theory strives to contextualize risk factors because they think that the efforts to reduce the risk by changing behavior will be ineffective if there is no clear understanding of the process that leads to exposure.


Advantage with the theory “social conditions as fundamental causes of disease”

  • The socioeconomic status associated with the disease despite changes in intervening mechanisms, because they involve access to resources such as money, knowledge, power, prestige, social support, and social network. All that can be used to avoid risks or to minimize the consequences of the disease once it occurs. SES and social networks are used by medical sociologists and social epidemiologists as potential fundamental causes (Link & Phelan, P. 87).

  • Theory that can take in the account variables such as race, ethnicity and gender are advantaged because that are critical issues because they are so closely tied to resources like money, power, prestige, and/or social (Link & Phelan, P. 87).

  • Socioeconomic resources like money, knowledge, power, and social connectedness are health related because those who command the most resources are best in avoiding the risks and the consequences of the disease. That can strengthen the theory clamed (Link & Phelan, P. 87).

  • Because social and economic resources can be used in different situations and ways, dynamically the fundamental social causes have effects on disease even when the profile of risk factors changes radically (Link & Phelan, P. 88).

  • The fundamental social causes cannot be explained by the same risk factors at any given time (Link & Phelan, P. 88).


The disadvantage with the theory “social conditions as fundamental causes of disease” 

  • Focusing on the causal chain that takes only the individually-based risk factors would lead us to actions that could limit our ability to improve the nation’s health. If no new diseases emerged then no new risks will be developed which means no new knowledge about risks emerged. Even no new treatments will be developed (Link & Phelan, pp. 87-90).

  • What puts people at risk of the risks before it may not be the same today (Link & Phelan, P. 87).

  • The fundamental social causes cannot be fully understood just by tracing the mechanisms that appear to link them to disease, that’s why we need to focus on mechanisms because multiple mechanisms maybe contribute to a persistent association between the cause and the effect. (Link & Phelan, pp. 87, 88).

  • “As a result, investigations of the relationship of such social factors to specific manifestations of the disease are of limited utility. Since only one manifestation of the social cause is measured in such studies, the full impact of the social cause goes unrecorded” (Link & Phelan, P. 88).

Social stratification, Social Stratification and Health Inequality- Stress and Depression, Psychology Topics

Social stratification


The theory of “education, learned effectiveness and health”

This theory sees education as the fundamental element of the socioeconomic status linking it to health and it is more important than income, wealth and occupation.  Education is a bridge between one generation and the next, education makes the individuals better at identifying, avoiding risky situations or habits and develops the learned effectiveness. It is cumulative and educated people will be quicker to exit the risky situations or correct the risky ways, and they will be able to manage or minimize the health problems that occur under life course “Education develops the capacity to find out what needs to be done and how to do it and develops habits and skills of self-direction” (Mirowsky and Ross, 2005, pp. 205-206).


  • Education is acquired first over the life course and contributes to many socioeconomic indicators for example contribute to the occupational class position and through that to income. Moreover induced the income. (Lahelma, Martikainen, Laaksonen, & Aittomäki, 2003, P. 327).

  • Education is important for health when the access to material resources is limited (Östergren 2018, p. 122). Because education is directly protective (Deaton 2018, p. 21).


  • Educational systems are not internationally uniformed (Elo 2009, p. 556).

  • Education is hard to achieve without support and it is associated with income, which means cost money, education and income interact as predictors of mortality (Östergren 2018, p. 122).

Tabell.1 Comparation and contrast

Link and Phelan’s theory Mirowsky and Ross’s theory
Conducted by medical sociologists and social epidemiologists Conducted by Sociologists.


Emphasis on individually-based risk factors Emphasis on education
Conducted 1995 Conducted 2005
Limited to individually-based risk factors Preventative for most aspects
Focusing on the causes of disease Focusing on the SES linking to health



We have also, several measures of socioeconomic status which are associated with health and mortality.  Contact us to purchase the product, there we will discuss the advantages and disadvantages of different measures of socioeconomic status (education, occupation-based indicators, income, and wealth) in health inequality research. We will argue also that it is plausible that different measures affect the health and the mortality through different pathways. Also, how that may affect the health of women and men from a gender perspective. As well as we will describe how inequality are responsible for greater stress, anxiety and mental health disease. Moreover, we will focus on the topic how to reduce stress physically and mentally and the interaction between physical and mental health.

Social Stratification and Health Inequality, Psychology Topics

Social Stratification and Health Inequality


Clougherty. J, E., Souza. K., &  Cullen. M, R. (2010) Work and its role in shaping the social gradient in health. New York Academy of Sciences. pp. 102-124. doi: 10.1111/j.1749-6632.2009.05338.x.


Deaton, A, Policy Implications Of  The Gradient Of Health And Wealth. Health affairs. Volume (21) pp. 13-29.


Doyal. L (2001) Sex, gender, and health: the need for a new approach. School for Policy Studies, University of Bristol, Bristol BS8 1TZ. Volume (323).


Elo. E (2009) Social Class Differentials in Health and Mortality: Patterns and Explanations in Comparative Perspective. Department of Sociology, Population Studies Center, University of Pennsylvania, Philadelphia, Pennsylvania 19104, Volume (35), pp. 553-572.


Hammarström. A., Johansson. K., Annandale. E., Ahlgren. C., Aléx. L., Christianson. M., Elwér. S., Eriksson. C., Fjellman,W. A., Gilenstam. K., Gustafsson. p, E., Harryson. L., Lehti. A., Stenberg. G., & Verdonk. P. (2013) Central gender theoretical concepts in health research: the state of the art Community Health. Journal of Epidemiology and Community Health. volume (68)185-190. doi:10.1 136/jech-201 3-202572.


Lahelma. E., Martikainen. P., Laaksonen.  M., & Aittomäki. A. (2003) Pathways between socioeconomic determinants of health. J Epidemiol Community Health, Volume (58), pp. 327–332.  doi: 10.1136/jech.2003.011148.


Link. B & Phelan. J. (1995) Social Conditions as Fundamental Causes of Disease. Journal of Health and Social Behavio, Volume (Extra Issu) pp. 80-94.


Mirowsky. J & Ross. C, R. (2005) Education, learned effectiveness and health. London Review of Education. Volume (3,) pp. 205-22.


Östergren. O (2018) Educational inequalities in mortality are larger at low levels of income: A register-based study on premature mortality among 2.3 million Swedes, 2006–2009. Department of Public Health Sciences, Stockholm University. pp 122-128.

No Comments Physiology FactsPsychology FactsPublic Health