Assertion:Stems of some plants protect them from browsing animals.
Reason:Axillary buds of stems of these plants are modified into thorns.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If assertion and reason are false.

Explanation

To solve the assertion and reason question, we will break it down into steps to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Stems of some plants protect them from browsing animals."
- This implies that certain plants have developed adaptations in their stems that serve as a defense mechanism against herbivorous animals that feed on them.

2. **Analyzing the Role of Stems**:
- Stems can be modified in various ways to serve different functions. In this case, the modification is for protection.
- Some plants have evolved to have thorns or spines on their stems, which can deter animals from eating them.

3. **Understanding the Reason**:
- The reason given is "Axillary buds of stems of these plants are modified into thorns."
- Axillary buds are the buds that form in the angle between the stem and a leaf. In some plants, these buds can develop into thorns.

4. **Connecting Assertion and Reason**:
- The reason explains how the stems of certain plants can protect against browsing animals by stating that the axillary buds are modified into thorns.
- This modification serves the purpose of defense, thus supporting the assertion.

5. **Conclusion**:
- Both the assertion and the reason are true. The reason accurately explains the assertion, as the presence of thorns (which are modified axillary buds) does provide protection to the plant from herbivores.

### Final Answer:
Both assertion and reason are true, and the reason is the correct explanation of the assertion.