Community is composed of individuals. If all the individuals have good personal health, the entire community will be healthy. Also, if the community is having hygienic surroundings, the individual health will be good. Thus, the two are interdependent, i.e. they depend on each other. The terms ‘overdependent’, ‘independent’ and ‘intradependent’ are not correct for this interdependent relation.

Transmission of disease means transfer of disease causing agents from diseased/infected person to the healthy one. AIDS is transmitted by sexual contact. Cholera and typhoid are transmitted by infected food and water while malaria is transmitted by the vector; female anopheles mosquitoes.

The diseases caused by microbes are generally transmitted quickly when microbes are transferred from the diseased to the healthy person and hence, they are termed “infectious” diseases, for e.g. common cold, skin infections, etc. 

Penicillin is an antibiotic obtained from the fungus ‘Penicillium notatum’ and it works against bacteria. Quinine and chloroquine are drugs which are used to treat malaria. Anti-Tetanus Serum (ATS) is a vaccine used to prevent tetanus. None of these is obtained from fungus and hence, they are not antibiotics.

 A disease transmitted by sexual contact is AIDS.

SARS is caused by bacteria (i.e. 1 is correct), AIDS is caused by Human Immunodeficiency Virus (HIV) (i.e. 2 is correct) and common cold is caused by different kinds of viruses (i.e. 4 is also correct). (1), (2) and (4) are correctly matched, but (3) is incorrect because malaria is caused by a protozoan, i.e. Plasmodium is transmitted by the vector, i.e. female anopheles mosquitoes.

Animal (dog and cat usually) bite causes rabies due to transmission of rabies virus. Typhoid and tetanus are caused due to bacteria transmitted by food, water, soil, etc while AIDS is caused by virus transmitted by exchange of body fluids between a healthy person and an infected person.

In elephantiasis, the person’s limbs, i.e. feet, legs, arms and hands are highly swollen due to accumulation of water in the cells. The person looks bulky and his limbs are swollen. It is compared to elephant’s limbs so the disease is termed “elephantiasis”. In ascariasis, the worm named ascaris infects the stomach and intestine, thereby making the person weak because they feed on the food material present in the blood of the person (host). Similarly, tuberculosis is caused due to bacteria and in this disease, lungs and respiratory systems are affected. In this, mucus begins to collect in lungs gradually leading to inefficient gaseous exchange, frequent cough and at later stages, bleeding occurs in the throat. Thus elephantiasis, ascariasis and tuberculosis are caused due to infectious agents and they take a long time inside our body as they are treated slowly. They leave behind long term health effects which make the body weak. Thus, they are chronic. But influenza, i.e. common cold lasts for few days. It affects us severely, but it does not make us weak later on. Hence, it is an acute disease.

Genetic disorders result from errors in the DNA of our body cells. Hormonal disorders (for e.g. excessive growth, appearance of facial hair in females, etc) are the results of imbalanced secretion of hormones produced within the body. Similarly, if any body organ malfunctions, i.e. it does not function in proper order, then it is an internal cause. But if there is malnutrition, then the cause is purely external and not within our body. We should remember that cause may be external or internal, but the effect is seen on the general health of our body.

Drinking milk will have no bad effect on the health as it is a source of almost all nutrients and it is recommended for good health.

A person will be healthy if he eats a proper diet (option 3), lives in a hygienic environment (option 4) and keeps his body fit by exercising regularly (option 1). Thus, options (1), (3) and (4) help a person to be healthy as these habits keep the germs away and thus, reduce the chances of getting infected by diseases. But, drinking alcohol is not a healthy practice as it adversely affects the nervous system and its prolonged consumption adversely affects the liver and general body health. Thus, (2) is the correct answer because drinking alcohol is responsible for the ill health of a person.

A defective gene that leads to a defect is a factor which is present inside the body cells of an organism. Hence, it is an internal factor. Extrinsic factors are those which are outside of the body and they include causative agents, diet, community, social system, etc.

 The AIDS virus does not spread through handshake. 

Most of the skin infections are caused by fungi. For example, ringworms. Bacteria and viruses cause internal infections like TB, influenza, etc. Mosquitoes can cause rashes on skin (it is not a disease) and may also transmit other diseases (not related to skin). Thus, (1), (2) and (3) are not suitable. So, only (4) is correct.

Health refers to physical, mental and social well-being. Thus, absence of any tension, anxiety (mental factors) and social problems contribute to health. But absence of work is not a factor that can make us healthy. Hence, (2) is the correct answer.

Common cold, pneumonia and tuberculosis are airborne diseases, i.e. they spread through air because their causative agents, i.e. virus and bacteria, are present in the air. On the contrary, malaria is not airborne because it is caused by Plasmodium, which spreads through the bite of female anopheles mosquitoes and is not present in the air. Thus, (4) is the correct answer.

Bacterial diseases are those diseases that are caused and transmitted by different bacteria. Typhoid, cholera and tuberculosis are caused by bacteria namely Salmonella typhii, Vibrio cholera and Bacillus calmettie, respectively. Dengue fever is caused by a virus, which is transmitted by the vector Aedes mosquito. Hence, option (3) is the correct answer.

Headache, diarrhoea and common cold last for some time and affect us severely for that short period. But they do not leave any of the effects like weakness. Thus, these are acute diseases. On the contrary, tuberculosis is chronic because it affects us for a long time and also makes the body weak, even after the infection is cured. It is caused due to bacteria and in this disease, the lungs and the respiratory system are affected. In this, mucus begins to collect in lungs, gradually leading to inefficient gaseous exchange, frequent cough and even bleeding in the throat at later stages. Hence, option (4) is the correct answer.

Haemophilia is a disease in which the blood does not clot whenever there is a wound/injury and it is a genetic disorder. It is not caused or spread by infectious agents. Thus, it is a non-infectious disease. Cholera, typhoid and malaria are caused due to microorganisms, which cause infection or disease in the digestive system, immune system and blood (also liver), respectively.

(a) Acute diseases: These diseases are severe, but short-spanned and get less time to cause prolonged poor health. (b) Chronic diseases: These diseases last for longer periods of time and take sufficient time to affect different parts of the body and lead to a poor health, which recovers after a long time. (c) Infectious diseases: These diseases spread from a diseased person to a healthy person due to the transmission of disease-causing organisms (for example, common cold). (d) Non-infectious diseases: These diseases do not spread from one person to another. For example, heart ailment, cancer, etc. They are not caused by infectious agents. The causative agents of these diseases are internal factors. 

“Health” refers to physical and mental well-being. If a person has psychological tension, his mental stability is disturbed. In this situation, we may say that he is unhealthy. Being wise or wealthy has no relation (under scientific logic) with health. Unhealthy people can also be rich and wise.

Sleeping sickness is caused by a tsetse fly.

Good health refers to a state when a person is free from any physical, mental or social illness. A healthy person will be efficient, happy, cheerful and will be social with others. Such a person will bring harmony in the society. Thus, options (1), (2) and (3) are correct for good health. Option (4) is not true because ill-minded people constitute a miserable society.

Worms are complex organisms with different tissues, organ system and body design. Also, they multiply by sexual reproduction which requires gamete formation, fertilisation, development, etc. before a new organism is born. Thus, it takes a longer time to produce new individuals that have complex body structures. So, due to the above reasons, the worms multiply slowly.

All factors which are outside our body are called “external” factors and they include pollution, alcohol and microbes, etc. But our immune system, i.e. the system of defensive mechanisms inside our body by which we fight against infection, is internal because it involves WBC’s of blood and its malfunctioning is not an external factor. So, (2) is the correct answer.

In any disease, the person falls ill but the ways in which the illness shows, e.g. headache, vomiting,          fever, etc. are different. These are called symptoms and they are characteristics of a particular disease, for e.g. gastric trouble in gastroenteritis. Causes or factors refer to reasons for disease. They can be pollution, bad habits, poor hygiene, etc. and cure refers to the treatment of disease. All these do not characterize a disease.

Myopia is a disease in which the focal length of eye lens is reduced and due to this a person is unable to see the objects at a large distance clearly. In kidney failure and cardiac failure, the body organs, i.e. kidney and heart respective fail to function properly. Thus, all three are due to improper functioning of body organs or parts. On the contrary, haemophilia is a genetic disease in which the blood does not clot. It is caused due to an error of DNA and the error is present on X chromosome but it is expressed in males only. Thus, D is the answer.

Infectious diseases are named so because they are caused due to “infection” which refers to the invasion by microorganisms. Thus, (1) is the correct answer. 

The health of the community is the responsibility of the civil society which is appointed by the government. In both cities & towns, such a body called municipal corporation (MC) makes all efforts to give good surroundings, remove pollution, avoid garbage and also to provide vaccines for maintaining health of the public. Thus (1) is the correct answer. On the contrary district administration takes care of the politics, security & other services (not related to health) in the entire district. Politicians are individuals who form the govt. which makes laws and proposals for the country. They may give orders to MC but community health is not their priority job. Civilians are the general public. They are not legally bound for maintaining community health. But if they take up this role, the community can become much better, cleaner and healthier.

Health is about being physically, mentally and socially well. Happiness, mutual understanding, and joy are the factors of mental and social health and if they are not present then a disease free person will be under stress and cannot be called healthy. In the light of these facts we can conclude that (1), (2) and (3) are correct. But as discussed above, option (4) is incorrect.

Syphilis is a bacterial disease which spreads through sexual contact. Tetanus (disease in which muscle contracts) and diphtheria are caused due to microbes and spread through air and soil, etc. Constipation (disease in which stools become hard) is an intrinsic disease, which is not spread from one person to the other.

AIDS virus can spread through body fluids, which include blood, semen (reproductive fluid of males containing sperms and nourishing materials), vaginal mucus, milk, etc. But it cannot be transmitted by skin to skin contact as in a handshake. Options (1), (2) and (3) refer to the methods in which one or the other body fluid is exchanged and hence they lead to AIDS infection.

Sickle cell anaemia is a genetic disorder in which the haemoglobin is defective and not efficient in O₂ transport. This defective haemoglobin distorts the shape of RBC in which it is stored and they look sickle-shaped. Hence, the name “sickle cell” is derived. Being sickle shaped, it is difficult for the RBCs to move more freely in the blood vessels and so supply of oxygen to different organs and cells become slow and hence, respiration and release of energy becomes low, thereby making us feel lethargic. 

Feeling anxiety at odd times is a sign of poor mental health. In such a situation, even if the person is physically fit, he is called unhealthy. So, (3) is the correct answer. “Happy” is an abstract feeling or state of mind which cannot be measured on scientific grounds. In general, being happy leads to good health. So, options (1), (2) and (4) are incorrect.

Disease causing organisms, i.e. causative agents are transferred from the diseased to the healthy person by an organism which itself does not get the disease. Such an agent is called a “vector”.

Infectious agents of common cold (virus), pneumonia (bacteria) and tuberculosis (bacteria) are the microbes which transfer through air, i.e. these are air borne diseases and affect our immune system, lungs and respiratory system, respectively. On the contrary, AIDS is caused due to HIV which is transmitted by sexual contact or exchange of body fluids only. Thus, (2) is the answer.

To protect themselves from adverse conditions, bacteria thicken or develop cell wall over their body. Cell membrane, i.e. plasma membrane cannot become thick enough to give protection while spores are the result of thickness and they germinate later.

AIDS, common cold and dengue fever are caused by viruses, e.g. HIV, common cold virus and dengue virus, respectively. Tuberculosis is caused by a bacterium named Bacillus calmettie and hence, (2) is the required answer.

Haemophilia is a genetic disease in which the blood does not clot. It is caused due to an error of DNA and the error is present on X chromosome but it is expressed in males only. Sickle cell anaemia is a genetic disorder in which the haemoglobin is defective and not efficient in O2 transport. This defective haemoglobin distorts the shape of RBC’s in which it is stored and they look sickle-shaped. Hence, the name “sickle cell” is derived. Being sickle shaped, it is difficult for the RBC’s to move freely in the blood vessels and so supply of oxygen to different organs and cells become slow and hence, respiration and release of energy becomes low, thereby making us feel lethargic. This disease is referred to as “anaemia”. Night blindness is a disease in which a person cannot see clearly in dim light due to defect in rod cells of retina. All these are genetic disorders. But, influenza is caused due to virus which is an external agent and hence, it is not a genetic disease. Thus, (1) (2) and (3) options are genetic diseases while (4) is not a genetic disorder.

Fever and cough last for a small duration and hence, they are acute. On the contrary, elephantiasis is a chronic disease, which lasts for a long time and makes the body and general health poor. In this disease, the person’s limbs, i.e. feet, legs, arms and hands, are highly swollen due to accumulation of water in the cells. The person looks bulky and his limbs are swollen. Hence, it is compared to elephant’s limbs and so the disease is termed “elephantiasis”. It should be noted that now small pox has been eradicated, but when it was prevalent, it used to last for a small time and cause death.