During biological nitrogen fixation, inactivation of nitrogenase by oxygen poisoning is prevented by.

The correct option is B

b) Leghaemoglobin

The correct option is (B):

Explanation for correct option:

Leghemoglobin, a pink oxygen scavenger pigment, protects nitrogenase during biological nitrogen fixation by preventing oxygen poisoning from inactivating the enzyme.

Description:

Explanation for incorrect option:

Option number (A)

Any of a variety of substances are made up of proteins and heme bonds. In many metabolic pathways, particularly cellular respiration, cytochromes serve as electron transfer agents.

option number (C)

One of the two main divisions of the carotenoid group, which is made up of carotenes and xanthophylls, are yellow pigments that are widely found in nature.

Option number (D)

Photosynthetic pigments called carotenes are crucial for photosynthesis. There are no oxygen atoms in carotenoids.

Final Answer: During biological nitrogen fixation, inactivation of nitrogenase by oxygen poisoning is prevented by leghemoglobin.