Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).

Assertion (A): A series of cellulolytic enzymes are employed in the wood degradation process by brown rot fungi.

Reason (R): Lignin is not degraded by these fungi, therefore, it has typical brown colour wood remains.

In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A).
• B. Both (A) and (R) are correct and (R) is the correct explanation of (A).
• C. (A) is correct but (R) is not correct.
• D. (A) is not correct but (R) is correct.

Hint:

Compare brown rot and white rot fungi in terms of which wood component each can break down.

Answer 1

The Correct Option is A

Compare brown rot with white rot to see why the reason fits. White rot fungi carry enzymes for both cellulose and lignin, so wood turns pale as lignin is removed, while brown rot fungi carry only cellulolytic and hemicellulolytic enzymes and cannot touch lignin. Because cellulose and hemicellulose, the lighter coloured components, are consumed while dark lignin stays behind, the wood shrinks, cracks into cube shaped pieces and keeps a brown colour. This cause and effect chain is exactly what Reason (R) describes, so it is a genuine explanation of Assertion (A), not just a separately true fact. \[\boxed{\text{Both correct, R explains A}}\]