1. After getting into the body of the person, thevirus enters into macrophages where RNAgenome of the virus replicates to form viral DNAwith the help of the enzyme reverse transcriptase.This viral DNA gets incorporated into host cell’sDNA and directs the infected cells to producevirus particles. The macrophages continue toproduce virus and in this way acts like a HIVfactory. Simultaneously, HIV enters into helper—————————— replicates and produceprogeny viruses.
(1) T-lymphocytes (T - helper)
(2) B-lymphocytes (CD - 4)
(3) Monocytes
(4) CD8 cells

2. Mark the labelled structures correctly -

3. Which of the following is not a component ofinnate immunity -
(1) Mucus coating of an epithelium
(2) Saliva
(3) Natural killer cell
(4) Antibodies

4. The human immune system consists of -
(a) lymphoid organs
(b) lymphoid tissues
(c) cells
(d) soluble molecules like antibodies
(1) a and b (2) b and c
(3) c and d (4) a, b, c and d

5. Somehow, modern-day life style has resulted in——————- of immunity and ——————-sensitivity to allergens – more and morechildren in metro cities of India suffer fromallergies and asthma due to sensitivity to theenvironment. This could be because of theprotected environment provided early in life.

(1) increasing, less 

(2) lowering, less

(3) lowering, more 

(4) increasing, more

C (1) A tonsils, B-lymph nodes, C - blood vessels (2) A-thyroid, B-lymph nodes, C - lymphatic vessels (3) B-lymph nodes, A-thymus, C - lymphatic vessels (4) C-lymph nodes, A-thymus, B-lymphatic vessels B