NEET2022Botany-Plant Anatomy
NEET 2022 Botany Secondary Growth MCQ Question
Type: MCQ-conceptual-Medium-Class 11
In old trees the greater part of secondary xylem is dark brown and resistant to insect attack due to:
A
secretion of secondary metabolites and their deposition in the lumen of vessels.
B
deposition of organic compounds like tannins and resins in the central layers of stem.
C
deposition of suberin and aromatic substances in the outer layer of stem.
D
deposition of tannins, gum, resin and aromatic substances in the peripheral layers of stem.
Correct Answer
Option B
Detailed Explanation
The heartwood of old trees is dark and resistant due to the deposition of tannins and resins, which protect against insects.
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