Answer: Option A. -> True
:
A
Some diseases persist for only a very short period, and these are called acute diseases. E.g. common cold, appendicitis, etc. Symptoms of other diseases prolong for several years or even a lifetime. These are called chronic diseases. E.g. elephantiasis, AIDS, etc.  

Answer: Option A. -> Vaccination 
:
A, C, and D
Some of the ways in which an infection can be prevented are as follows.
-Maintain personal hygiene.
-Keep kitchen clean by washing utensils, dishes, cooking area before and after preparing food.
-Vaccination 
-Keep both bathroom and toilet area clean.
-Avoid sharing personal belongings such as a razor, drinking glass, toothbrush, comb, etc.
-Do not travel or go to work when you fall ill.
-While visiting patients in hospitals, it is recommended to wear a mask or gown and if possible make use of sanitizing gels to prevent infection.

Answer: Option A. -> Common cold
:
A and B
Common examples of diseases caused by virus are common cold, influenza, dengue fever etc. Cholera is caused by bacteria and malaria is caused by protozoan microbes.
 

Answer: Option B. -> False
:
B

An acute disease is a disease that follows a short course. Elephantiasis refers to a parasitic infection that causes extreme swelling in the arms and legs. The disease is caused by the filarial worm, which is transmitted via the female culex mosquito. Ailments that last for a long time, even as much as a lifetime, are called chronic diseases. Elephantiasis can last for a very long time and has long-term effects on the body. Therefore, it is a chronic disease.

Answer: Option A. -> Immunity
:
A
The ability of an organism to resist disease, either through the activities of specialized blood cells or antibodies produced by them is termed as immunity.Some people are more immune against certain diseases than other people. Thus, immunity is responsible for giving protection against certain diseases to some people.

Answer: Option A. -> Breathing in germs in the air
:
A and B

The most common way to catch infectious illnesses like cold and influenza is through droplet infection through air. Touching the mouth, nose, or eyes with hands that are contaminated with disease-causing germs is another common way to get infected by these diseases. 

Answer: Option A. -> immune cells
:
A
The immune system of our body is specialised in killing the infecting organisms with the help of immune cells. These cells go into action each time when infecting microbes enter the body.

Answer: Option B. -> Many antibiotics are produced by bacteria.
:
B

Antibiotics are substances produced by some bacteria or fungi, or can even be produced synthetically. Antibiotics works against the pathogenic bacteria. Anitibiotics disrupt the cell wall formation in them and thus, kill the bateria and stop their multiplication. 
Antibiotics work only against bacteria and simply attack them. They are not responsible for the strengthening of immune system. They have multiple side effects like diarrhea, nausea, vomiting, rash, stomach upset etc.

Answer: Option A. -> True
:
A
Effective prevention of infectious diseases in the community is achieved through access to public hygiene and immunisation.
A community with the availability of the better hospitals and resources like vaccines to improve immunity, medicines, clean environment etc. eliminates the disease first hand and contributes to the eradication of the infectious diseases effectively and permanently.

Answer: Option A. -> Human cells don't have cell wall.
:
A
The antibiotic penicillin blocks the bacterial processes that build the cell wall. Due to the lack of cell wall, the organism dies easily. Human cells don’t have a cell-wall. So penicillin cannot have such an effect on human cells.