Question

Assertion :Movement of materials inside phloem is bidirectional, both upwards and downwards. Reason: Movement of molecules inside xylem is unidirectional always upwards.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

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

The movement of water and minerals in xylem is unidirectional and the movement of phloem sap in phloem is bidirectional respectively. Plants need water for their growth, and it uptakes water through the roots. Water that is taken by the roots has to reach all the leaves or branches, here the xylem function as transportation of water. Therefore, the movement of water and minerals in xylem is always an unidirectional and always upwards. Whereas, the movement of phloem is bidirectional this is because, once the food is synthesized it is the phloem that transfers the food to all the parts of plants wherever it is necessary. So, movement of materials inside phloem is bidirectional, both upwards and downwards.

So, the correct answer is option B.