Thick unbranched roots found in corms and rhizomes of some plants are

Options

A. Reproductive
B. Contractile
C. Root thorns
D. Stilt roots.

Answer

To solve the question regarding the type of roots found in corms and rhizomes of some plants, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks about the type of roots that are thick and unbranched, specifically found in corms and rhizomes of certain plants.

2. **Identify the Options**: The options provided are:
- Reproductive roots
- Contractile roots
- Root thorns
- Stilt roots

3. **Analyze Each Option**:
- **Reproductive Roots**: These are typically involved in the reproduction of the plant, not necessarily thick or unbranched.
- **Contractile Roots**: These roots are known for their ability to pull the plant deeper into the soil as the stem elongates. They are indeed thick and unbranched.
- **Root Thorns**: These are modified roots that serve as a defense mechanism, not typically thick or unbranched.
- **Stilt Roots**: These roots provide support to the plant and are usually found in plants that grow in unstable soils, but they are not specifically thick and unbranched.

4. **Select the Correct Answer**: Based on the analysis, the roots that are thick and unbranched found in corms and rhizomes are **contractile roots**.

5. **Conclusion**: Therefore, the correct answer to the question is **contractile roots**.