Question

Choose the forms in which most plants absorb nitrogen.

(i) Proteins

(ii) Nitrates and nitrites

(III) Urea

(iv) Atmospheric nitrogen

• A. (i) and (ii)
• B. (ii) and (iii)
• C. (iii) and (iv)
• D. (i) and (iv)

Answer 1

The correct option is B

(ii) and (iii)

The correct option is B.

Explanation of correct option:

• The atmospheric nitrogen is converted into nitrates and nitrites by the soil bacteria. The plant roots take these forms of nitrogen from the soil.
• The plants can also absorb another form of nitrogen called urea from the soil. Its hydrolysis results in ammonia that plants can use.

Explanation of incorrect options:

Option A:

• Plants do not absorb proteins. They absorb nitrates and nitrites.

Option C:

• Plants do not take atmospheric nitrogen from the air, but some plants absorb urea through the soil.

Option D:

• Plants do not absorb atmospheric nitrogen and proteins.

Therefore, nitrates, nitrites, and urea are the forms of nitrogen taken up by the plants.