Pneumonia can cause by a virus, fungi, bacteria, etc. They can be transmitted from a contaminated person to a healthy person by sneezing, coughing, contaminated objects, air, etc. Thus it is considered as a communicable disease. So, the correct answer is option A.

Simple goitre is caused due to the lack of iodine in the diet which causes hypothyroidism. It is a deficiency disease and is easily reversible by a proper intake of iodine. Iodine helps in the synthesis of thyroxine hormone. Due to the above-stated reasons, the answer is true.

• Infectious diseases are those diseases which are caused by microorganisms like fungi, bacteria, virus, parasites. 
• Diphtheria is an infectious disease caused by the bacterium Corynebacterium diphtheria. It affects the mucous membrane of the throat and upper respiratory tract. Coronary thrombosis is caused due to accumulation of cholesterol in the walls of arteries. 
• Cancer is caused by mutation, radiation, etc. Diabetes mellitus is caused by insufficient production of insulin.

(i) Hepatitis primarily affects liver - true

Infectious diseases are those that can spread from a diseased person to a healthy person. They are also called communicable diseases. 

Jaundice is a non-communicable infectious disease that is caused due to excessive secretion of bilirubin, that is not completely filtered by the blood. It is mostly caused due to Hepatitis virus, that infects the hepatic system.

• Hay fever is an allergic reaction caused by pollen dust or indoor allergens.
  
• Such allergens cause the inflammation of the mucous membranes of the eyes and nose.
• The main symptoms include a runny nose and watery eyes.
• So, the correct answer is 'True'.

Genus Alexandreum of dinoflagellates secretes neurotoxin saxitoxins which are the causative agents of paralytic shellfish poisoning (PSP). Molluscs such as mussels and clams feed on a large number of dinoflagellates, human consumption of those molluscs causes paralysis. 

The causative agent of mad-cow disease is a prion. Bovine spongiform encephalopathy (BSE), commonly known as mad cow disease, is a fatal neurodegenerative disease or encephalopathy in cattle that causes a spongy degeneration in the brain and spinal cord. It is caused due to a prion. A prion is an infectious agent, specifically a protein in a misfolded form. The protein itself, whether in its misfolded or its correctly folded form, can be referred to as the prion protein (PrP). A protein as an infectious agent stands in contrast to all other known infectious agents, like viruses, bacteria, fungi, or parasitesall of which must contain nucleic acids.

Leukaemia is blood cancer.
Polycythemia is an abnormally increased concentration of hemoglobin in the blood.
Tay-sachs disease is hexosaminidase A deficiency.
Leucopenia is a reduction in the number of white blood cells (leucocytes) caused by the deficiency of folic acid.
Therefore, the correct answer is option B.

AIDS is caused by HIV virus and transmits sexually.
Jacob syndrome is characterized by an extra copy of Y chromosome in a male. Thalassemia is an inherited autosomal recessive blood disorder characterized by abnormal formation of hemoglobin. Whereas asthma is a respiratory condition caused by attacks of spasm in the bronchi of the lungs, causing difficulty in breathing. One of its cause is coming in contact with some air-borne allergens or exposure to some viral infections in infancy or in early childhood when the immune system is developing.
Thus, the correct answer is option B.

Antibiotics are used against bacterial diseases and malaria is a protozoan disease.

The severity of the disease manifestations depends on the number of microbes present in the body. Smaller is the number of microbes in the body, lesser are the symptoms of a disease. On the contrary, if microbe exists in large number in the body, disease can be severe and life-risking.

Common cold spreads through the mucus of the infected people during sneezing and coughing.

A non-communicable disease (NCD) is a disease that is not transmissible directly from one person to another. Communicable diseases are infectious.

Communicable diseases are the disease that can spread from one person t another by any means of body or blood contact common cold can spread by sneezing in public without covering mouth and chicken pox spreads in the same manner as the cold by sneezing it can also spread through the fluid from the blisters.

An allergy is a non-communicable disease and is a medical condition that makes a person feels unwell, when they eat or come in contact with a particular substance like itchy ears and eyes, eating of food like milk and egg. It occurs when the body’s immune system overreacts to a normally harmless substance.

Communicable diseases spread from one person to another or from an animal to a person. The spread often happens via airborne viruses or bacteria, but also through blood or other bodily fluid. The terms infectious and contagious are also used to describe communicable disease.

Rabies is caused by rabies virus. It is caused due to an animal bite which readily transfers the pathogens to the blood of the infected. Saliva from an infected animal can also transmit rabies if the saliva comes into contact with the mouth, nose, or eyes. Infected vertebrates like birds, rodents, other larger animals mainly dogs are the most common animal involved. The rabies virus travels to the brain by following the peripheral nerves and affect the neurological junctions.

Leprosy is an infectious disease. It affects the peripheral nerves, skin, upper respiratory tract, eyes, and nasal mucosa. It is caused by a bacillus bacterium known as Mycobacterium leprae. It can be considered as a mild infection because it can be easily cured by the drugs like dapsone. 

Deficiency diseases are the diseases that are caused due to deficiency of vitamin or minerals in the food and is not a communicable disease as it cannot be transferred for person to person by touch or any fluid as it is not caused by any bacteria or virus.

A goiter is an abnormal swelling of the thyroid gland that causes a lump to form in the neck. There can be many possible causes including an under or overactive thyroid gland due to iodine deficiency
So, the correct answer is 'Thyroid gland'

Beriberi is a deficiency disorder of thiamine (vitamin B$ _{1}$) that affects many systems of the body, including the muscles, heart, nerves, and digestive system. Rickets is defective mineralization or calcification of bones due to deficiency or impaired metabolism of vitamin D. Scurvy is a disease resulting from a deficiency of vitamin C. Scurvy presents initially with fatigue, followed by formation of spots on the skin, spongy gums, and bleeding from the mucous membranes. Thus, the correct answer is option B.

A chronic condition is a severe disturbance in the metabolism of the body which is long lasting. The term chronic is usually applied when the course of the disease lasts for more than three months. Such chronic disease cannot be cured easily.

Chronic disease is a long-lasting condition that can be controlled but not cured. The term chronic is usually applied when the course of the disease lasts for more than three months. Common chronic diseases include arthritis, asthma, cancer, diabetes and viral diseases such as hepatitis C and HIV/AIDS.

Droplet infection is the infection which is transmitted by the oral discharge during coughing and sneezing. It is a direct method of infection where the pathogens are easily transmitted from the carrier to the healthy host.

Asthma is a respiratory condition marked by attacks of spasm in the bronchi of the lungs, causing difficulty in breathing. It is usually connected to the allergic reaction or other forms of hypersensitivity. Hay fever is the common name for allergic rhinitis. It is an allergic reaction to allergens, or triggers, breathed in through the nose. When one of these allergens is breathed in, there is an immune response in the lining of the nose. This causes the nasal passages to become swollen and inflamed. Asthma and hayfever are closely linked, and approximately 80% of people with asthma also suffer from hayfever.

Tuberculosis (TB) is an acute or chronic infection caused by the tubercle bacillus Mycobacterium tuberculosis. Viral fever is an acute viral infection. The most common viral fever is the seasonal flu. The virus is spread when an infected person coughs or sneezes. The common cold is a viral infectious disease of the upper respiratory tract which primarily affects the nose. It usually resolves in seven to ten days, with some symptoms lasting up to three weeks. Examples of chronic illnesses are cancer, AIDS, kidney disease and diabetes.

Goiter is the condition caused by the deficiency of thyroid hormone. The thyroid gland (a gland in the neck that produces hormones) needs iodine that helps to manufacture thyroid hormones (chemicals released into the bloodstream that controls the body's growth and metabolism). If our body doesn't receive enough iodine, our thyroid gland becomes underactive and increases in size called as goiter.

Parkinson is a disease which can stay for a lifetime. Hence, it is a chronic disease. Therefore, (b) is the correct answer.

Public health programs are important in educating the public and promoting healthy lifestyles and awareness about chronic diseases like cancer diabetes. Therefore, (c) is the correct answer.

Ailments which can last for a long time, as much as a lifetime are called as chronic diseases. These are mainly caused due to severe metabolic disorder. The term chronic is usually applied when the course of the disease lasts for more than three months. chronic diseases constitute a major cause of mortality, chronic non-communicable conditions to be by far the leading cause of mortality in the world.

Ailments which can last for a long time, as much as a lifetime are called as chronic diseases. These are mainly caused due to severe metabolic disorder.

Infectious diseases are disorders caused by microorganisms such as bacteria, viruses, fungi or parasites. Therefore, (c) is the correct answer.

Common cold persist for a very short duration. Hence, it is an acute disease. Other mentioned diseases Diabetes Cancer and Alzheimers persists for a very long duration. Therefore, (d) is the correct answer.

A particular concern is the rising rates of overweight and obesity. Obesity itself is a medical condition and not a disease, but it constitutes a major risk factor for developing chronic illnesses, such as diabetes, stroke etc. Therefore, (a) is the correct answer.

Sometimes, NCDs result in rapid deaths as seen in certain diseases such as heart diseases, stroke, cancers etc. NCDs are distinguished only by their non-infectious cause, and not necessarily by their duration. Therefore, (c) is the correct answer.

The correct answer is 'both B and C'

Infectious diseases are disorders caused by organisms — such as bacteria, viruses, fungi or parasites. AIDS which is caused by HIV is an infectious disease.

A contagious disease is a subset category of transmissible diseases (can transmit from person to another), usually infections or some non-infection diseases, which are transmitted to other persons, either by physical contact with the person suffering the disease, or by casual contact with their secretions or objects touched by them or airborne route among other routes. 

Histamine is a nitrogenous compound which gives a local immune response. Histamine is involved in the inflammatory response as well as it acts as a neurotransmitter. As a part of the immune response to foreign pathogens, histamine is produced by the mast cells and the basophil cells in the nearby connective tissue against the allergic reaction. Sneezing happens because of histamine-associated sensory neural stimulation. 

Appendicitis or epityphlitis is inflammation of the vermiform appendix. The inflamed appendix is filled with pus and causing pain. The symptom of appendicitis includes abdominal pain, nausea, vomiting and decreased appetite. 

A. Pellagra is caused by the deficiency of vitamin B-3 and it causes dementia, diarrhea, and dermatitis (three Ds).

Endogenous chemical agents are those that originate from within the organism, tissue or cell. Endogenous chemical agents and genetic mutations are collectively called intrinsic or internal factors affecting human health. The diseases caused by intrinsic factors are called organic or metabolic diseases. Chemicals which may be endogenous are urea, uric acid, hormones and enzymes. Uric acid is produced within the body of human beings and if it does not get eliminated by kidneys, then it may result in a serious disease known as gout which is due to the accumulation of uric acid in joints.

Non-infectious disease is a kind of disease which are not caused by pathogens. Instead they are caused by lifestyle factors, environmental toxins or gene mutations.

• Diabetes mellitus is commonly known as diabetes.
• It is a group of metabolic disorders characterized by high blood sugar levels over a prolonged period.
•  Symptoms of high blood sugar include frequent urination, increased thirst, and increased hunger. 
• When you have diabetes, excess sugar (glucose) builds up in your blood. If your kidneys can't keep up, the excess sugar is excreted into your urine, dragging along fluids from your tissues. Hence, A man suffering from diabetes mellitus drinks water more frequently as he has to eliminate from the blood extra glucose.

 Metabolic reactions are those chemical reactions through which a complex substance break into smaller molecules and produces the energy which helps in completing the life cycle of an organism. Metabolic reactions can take place in a living system e.g. digestion and respiration in the living organism. metabolic reactions also take place in an isolated cell-free system e.g. reactions take place in the test tube. Metabolic reactions take place in unicellular as well as multicellular organisms.

Tetanus (lockjaw) is an acute infectious disease, affecting the nervous system, caused by the bacterium Clostridium tetani. Infection occurs by contamination of wounds by bacterial spores.

Congenital diseases are anatomical or physiological abnormalities present since birth, e.g., haemophilia, colour blindness, sickle-cell anaemia, Down's syndrome, Turner's syndrome.

As nose leads to lungs, so microbes that enter the body through nose will affect the lungs.

Through sneezing, the water droplets carrying the microbes enter into the healthy person.

Exophthalmic goitre is characterised by increased body temperature, high blood pressure, bulging of eyeballs, weight loss despite increased appetite, rapid heart beat, nervousness, etc. Endemic goitre is characterised by abnormal cold sensitivity, excessive fatigue, insomnia, low blood pressure.

Allergies are the common diseases that seen in most of the people due to hypersensitivity. It is also defined as the overreaction of the immune system or deviation from the immunity process. This may be due to change in the environment conditions or by any food item. The most common environmental based allergy is the allergy to pollen grains and in food is the peanuts. Thus, the correct answer is option A.

Varicose veins are the swelling of the veins that are present under the skin. This is due to the loss of elasticity in the walls of the veins that causes them to stretch out and slows down the blood to move back to the heart. This leads to increased blood pressure and the veins underneath the skin will swell. Thus, the correct answer is option A.

Beriberi is a deficiency disorder of thiamine (vitamin B$ _{1}$) that affects many systems of the body, including the muscles, heart, nerves, and digestive system. B$ _{1}$ vitamin benefits include prevention of abnormal development of muscles and nerves, pricking and burning sensation in the toes and feet, leg cramps and atrophy or wasting of the muscles.

Viral diseases are severe infectious diseases which spread rapidly from one person to the other. Pancreatic necrosis (IPN) is a viral disease which occurs in salmon fish. It is mainly caused due to the premature killing of the cells in the living tissues.

A chronic condition is a condition where the metabolism of the body is severely disturbed and it last for longer duration. Common chronic diseases include arthritis, asthma, cancer, COPD, diabetes and viral diseases such as hepatitis C and HIV/AIDS.

Explanation: An epidemic occurs when an infectious disease spreads rapidly among too many people.

Explanation: Communicable diseases are caused by pathogens passed from one human to another. Pathogenic organisms are of five main types: viruses, bacteria, fungi, protozoa, and worms.

Explanation: Communicable diseases are caused by pathogens passed from one human to another.

Foot-and-mouth disease or hoof-and-mouth disease is an infectious and sometimes fatal viral disease that affects cloven-hoofed animals, including domestic and wild bovine. The virus causes a high fever for two or three days, followed by blisters inside the mouth and on the feet that may rupture.

Explanation: The common cold is a viral infection of the upper respiratory tract. The most commonly implicated virus is a rhinovirus (30% to 80%).

Acidosis is due to rapid fat catabolism. This leads to high levels of acetoacetic acid, which is converted to acetone and beta-hydroxybutyric acid. These three molecules known as ketone bodies. The presence of excreted ketone bodies in urine and in expired air is used as one diagnostic test for diabetes mellitus. Thus, the correct answer is option B.

Explanation: Non-communicable disease (NCD) is a medical condition or disease that is noninfectious or non-transmissible. NCDs can refer to chronic diseases which last for long periods of time and progress slowly.

Explanation: Communicable diseases are caused by pathogens passed from one human to another. Pathogenic organisms are of five main types: viruses, bacteria, fungi, protozoa, and worms. Whereas, most skin cancers are caused by exposure to the sun.

Explanation: You can also get enteritis when you come into close contact with other people or animals that are infected. This is less common.

Explanation: Communicable diseases are caused by pathogens passed from one human to another. Non-communicable disease (NCD) is a medical condition or disease that is non-infectious or non-transmissible.

Communicable diseases are caused by pathogens passed from one human to another. Use soap, warm water and disposable paper towels. Wash your hands frequently and avoid direct contact.

Dehydroepiandrosterone (DHEA) is an important endogenous steroid hormone. It is the most abundant circulating steroid hormone in humans. DHEA is used to treat systemic lupus erythematosus (SLE), osteoporosis, multiple sclerosis (MS), low levels of steroid hormones (Addison disease), depression, schizophrenia, chronic fatigue syndrome (CFS), and to slow the progression of Parkinson disease. It is also used for preventing heart disease, breast cancer, diabetes, and metabolic syndrome. DHEA is used for weight loss, for decreasing the symptoms of menopause, and for boosting the immune system. It is naturally produced in the human body.