Respiratory structures of two different animals — a fish and a human being are as shown.

Observe (a) and (b) and select one characteristic that holds true for both of them.

1. Both are placed internally in the body of animal.
2. Both have thin and moist surface for gaseous exchange.
3. Both are poorly supplied with blood vessels to conserve energy.
4. In both the blood returns to the heart after being oxygenated.

The length of small intestine in a deer is more as compared to the length of small intestine of a tiger. The reason for this is :

1. Mode of intake of food
2. Type of food consumed
3. Presence or absence of villi in intestine
4. Presence or absence of digestive enzymes

Observe the diagram of an activity given below. What does it help to conclude, when the person exhales into the test-tube?

1. Percentage of carbon dioxide is more in inhaled air.
2. Fermentation occurs in the presence of oxygen.
3. Percentage of carbon dioxide is more in exhaled air.
4. Fermentation occurs in presence of carbon dioxide

The radius of curvature of a converging mirror is 30 cm. At what distance from the mirror should an object be placed so as to obtain a virtual image?

1. Infinity
2. 30 cm
3. Between 15 cm and 30 cm
4. Between 0 cm and 15 cm