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In roots, the primary xylem is called ex...

In roots, the primary xylem is called exarch. because -

A

The protoxylem lies towards the centre and the metaxylem lies towards the periphery

B

The protoxylem lies towards the periphery and the metaxylem lies towards the centre

C

Both the protoxylem and the metaxylem lies towards the centre

D

The protoxylem is surrounded by the metaxylem.

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### Step-by-Step Solution 1. **Understanding Primary Xylem**: The primary xylem is a type of vascular tissue responsible for the transport of water and minerals in plants. It is formed during the primary growth of the plant. 2. **Definition of Exarch Condition**: The term "exarch" refers to the arrangement of xylem in which the protoxylem (the first-formed xylem) is located towards the periphery (outer part) of the root, while the metaxylem (the later-formed xylem) is situated towards the center. 3. **Arrangement of Xylem in Roots**: In roots, the primary xylem exhibits an exarch condition. This means that: - The protoxylem is positioned closer to the outer edge of the root. - The metaxylem is positioned closer to the center of the root. 4. **Significance of Exarch Arrangement**: This arrangement is significant for the plant's growth and development. It allows the plant to efficiently transport water and nutrients from the soil while providing structural support. 5. **Contrast with Endarch Condition**: In contrast, an "endarch" condition would have the protoxylem located towards the center and the metaxylem towards the periphery. This is not the case in roots, hence the term exarch is used. 6. **Conclusion**: Therefore, the primary xylem in roots is called exarch because the protoxylem is located towards the periphery and the metaxylem is located towards the center.
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