Assertion (A): The main pulmonary artery pumps oxygenated blood from the right ventricle into the lungs.

Reason (R): Inside the lungs, the artery divides and divides several times to form capillaries around the air sacs.

1. A is True, and R is false.
2. A is False, and R is true.
3. Both A and R are true.
4. Both A and R are false.

The diagram given alongside is an experimental set up mimicking a certain process occurring in living beings. Study the figure and answer the following questions :

(i) Name the process and define it.

(ii) What are the two phases of the above mentioned process shown as (A) and (B) ?

(iii) Name the particular organs of the body shown in the figure with :
(a) Bell jar (b) Balloons (c) Rubber sheet

(iv) How do these phases (A) and (B) differ with respect to the position of ribs ?

(v) Does the breathing rate of a young boy and an old person differ ? Explain.

The muscular sheet which divides the body cavity into thorax and abdomen is termed as :

1. Inner pleura
2. Rib cage
3. Outer pleura
4. Diaphragm

Describe in brief the function of ribs and diaphragm in breathing.