Bamboo or grass stem elongates by the activity of :

Options

A. primary meristem
B. apical meristems
C. secondary meristem
D. intercalary meristems

Explanation

To determine how bamboo or grass stems elongate, we need to analyze the types of meristems involved in plant growth. Here’s a step-by-step solution:

### Step-by-Step Solution:

1. **Understanding Meristems**:
- Meristems are regions in plants where cells divide and contribute to growth. They can be classified into different types based on their location and function.

2. **Types of Meristems**:
- **Primary Meristem**: These arise from the meristematic tissue and are responsible for the initial growth of the plant. They are involved in the formation of primary tissues.
- **Apical Meristem**: A type of primary meristem located at the tips of roots and stems. It is responsible for the elongation of these parts.
- **Secondary Meristem**: These are involved in the thickening of stems and roots, contributing to secondary growth.
- **Intercalary Meristem**: Found at the internodes, which are the segments between nodes. This type of meristem is crucial for the elongation of stems in certain plants, particularly grasses and bamboos.

3. **Identifying the Correct Meristem for Bamboo and Grass**:
- Bamboo and grass stems elongate primarily due to the activity of the intercalary meristem. This meristem allows for growth in length at specific locations along the stem, particularly in the internodes.

4. **Conclusion**:
- Therefore, the correct answer to the question is that bamboo or grass stems elongate by the activity of the **intercalary meristem**.

### Final Answer:
Bamboo or grass stem elongates by the activity of the **intercalary meristem**.

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