Assertion :Heartwood does not comprise dead elements without any lignified walls. Reason: The peripherial region of the secondary Xylem is lighter in colour and is involved in the conduction of water and minerals from root to leaf.

Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

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Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

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Assertion is correct but Reason is incorrect

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Both Assertion and Reason are incorrect

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Solution

The correct option is D Both Assertion and Reason are incorrect
The greater part of secondary xylem in old trees is dark brown due to deposition of organic compounds in the central or innermost layers of the stem. This region comprises dead elements with highly lignified walls and is called heartwood. It does not conduct water but gives mechanical support to the stem.
The peripheral part of the secondary xylem is lighter in colour and is known as the sapwood. The walls are not lignified and there is no deposition of organic compounds. It is involved in the conduction of water and minerals from root to leaf.
So, the correct option is D.

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