The radicle elongates and forms__________

Options

A. Primary root
B. Secondary root
C. Rootlets
D. Tertiary root

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks what structure is formed when the radicle elongates. The radicle is the part of the embryo in a seed that develops into the root.

2. **Identifying the Components of the Embryo**: The embryo consists of three main parts: the radicle, the plumule, and the cotyledons. The radicle is specifically responsible for developing into the root system.

3. **Role of the Radicle**: During germination, the radicle elongates. This elongation is crucial as it marks the beginning of root development.

4. **Formation of the Primary Root**: As the radicle elongates, it develops into the primary root, which is the main root of the plant. This root is typically thick and serves as the anchor for the plant.

5. **Development of Lateral Roots**: The primary root can give rise to lateral roots, which include secondary and tertiary roots. These roots help in further anchoring the plant and absorbing water and nutrients.

6. **Conclusion**: Therefore, when the radicle elongates, it forms the primary root.

**Final Answer**: The radicle elongates and forms the **primary root**.

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