Why is it that during changing weather, one is advised to avoid closed, crowded and airconditioned places like cinema halls etc.?

In the figure, structure of an antibody molecule is shown. Name the parts A, B and C.

Show A, B and C in the diagram.

If a regular dose of drug or alcohol is not provided to an addicted person, he shows some withdrawal symptoms. List any four such withdrawal symptoms.

The harmful allele of sickle cell anaemia has not been eliminated from human population. Such afflicted people derive some other benefit. Discuss.

Lymph nodes are secondary lymphoid organs. Explain the role of lymph nodes in our immune response.