Increase in girth of the plant as a result of the activities of primary and secondary lateral meristems is called.

Options

A. primary growth
B. lateral growth
C. secondary growth
D. intercalary growth.

Explanation

To answer the question regarding the increase in the girth of a plant due to the activities of primary and secondary lateral meristems, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Types of Growth in Plants**:
- Plants exhibit two main types of growth: primary growth and secondary growth.
- Primary growth is responsible for the elongation of the plant, while secondary growth is responsible for the increase in girth (thickness).

2. **Identify the Role of Meristems**:
- Meristems are regions of undifferentiated cells in plants that are capable of division and growth.
- There are two types of meristems relevant to this question: apical meristems (which contribute to primary growth) and lateral meristems (which contribute to secondary growth).

3. **Focus on Lateral Meristems**:
- Lateral meristems include the vascular cambium and cork cambium.
- The vascular cambium is responsible for producing new vascular tissue (xylem and phloem), while the cork cambium produces the outer protective layer of the plant.

4. **Define Girth Increase**:
- The term "girth" refers to the thickness of the plant stem or trunk.
- The increase in girth is specifically associated with the activities of lateral meristems, which contribute to secondary growth.

5. **Conclusion**:
- Given that the question asks about the increase in girth due to the activities of primary and secondary lateral meristems, the correct term for this growth is **secondary growth**.

### Final Answer:
The increase in girth of the plant as a result of the activities of primary and secondary lateral meristems is called **secondary growth**.

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