1.    (i) (b)

(ii) (d)

(iii) (a)

(iv) (c)

2.    Fill in the blanks.

(i) The blood from the heart is transported to all parts of the body by the arteries.

(ii) Hemoglobin is present in red blood cell.

(iii) Arteries and Veins are joined by a network of capillaries.

(iv) The rhythmic expansion and contraction of the heart is called heartbeat.

(v) The main excretory product in human beings is urea.

(vi) Sweat contains water and salts.

(vii) Kidney eliminates the waste materials in the liquid form called urine.

(viii) Water reaches great heights in the trees because of suction pull caused by transpiration.

3.    (a) (i) Xylem

(b) (ii) in dim light.

4.    Different parts of the body perform different works. For example, in plants roots absorb water and leaves prepare food utilizing the water. The food is also required by root. So, there is no utility of water absorb by roots if it does not reach leaf or food prepared by leaf if it does not reach to root. So, transport system is necessary.

5.    Blood cannot clot without the platelets. So, if there is any cut, blood continue to flow and ultimately the person dies.

6.    Small pores in leaves of plants are called stomata.

Functions of stomata-

(i) Exchange of carbon dioxide and oxygen.

(ii) Transpiration to remove excess of water.

7.    Due to transpiration, a suction pressure develops which help in transpiration of water.

8.    Red blood cells, white blood cells, platelets and plasma.

9.    Blood carries digested food and oxygen to all parts of body. It also carries away the waste products.

10.   The presence of hemoglobin.

11.    Heart collects and distributes blood from and to all parts of body. Rhythmic contraction and relaxation creates pressure to send blood to all parts of the body.

12.    The waste products produced in various metabolic process in our body are harmful for the body.