Assertion (A): Nitrogen is an essential element for plant growth and is taken up by plants in the form of inorganic nitrates or nitrites.

Reason (R): The soil is the nearest and richest source of raw materials like Nitrogen, Phosphorus and other minerals for the plants.

1. Both A and R are true, and R is the correct explanation of A.
2. Both A and R are true, and R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

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.

A student was asked to write a stepwise procedure to demonstrate that carbon dioxide is necessary for photosynthesis. He wrote the following steps. The wrongly worded step is:

1. Both potted plants are kept in dark rooms for at least three days.
2. Bottom of the bell jars is sealed to make them air tight.
3. Both potted plants are kept in sunlight after the starch test.
4. A leaf from both the plants is taken to test the presence of starch.

Assertion (A): Sun appears reddish at the time of Sunrise and Sunset.

Reason (R): Distance travelled by sunlight in the atmosphere is lesser during sunrise and sunset as compared to noon.

1. Both A and R are true, and R is the correct explanation of A.
2. Both A and R are true, and R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.