Secondary tissues of a plant -

Options

A. Add to the length of roots and shoots
B. Add to the diameter of existing roots and shoots
C. Are found only in the embryo
D. Are found only in the seedling

Answer

### Step-by-Step Text Solution:

1. **Understanding Secondary Tissues**: Secondary tissues in plants are responsible for the increase in the diameter of roots and shoots. They are produced by the lateral meristems, which include the vascular cambium and cork cambium.

2. **Role of Secondary Tissues**: Unlike primary tissues, which contribute to the length of the plant (primary growth), secondary tissues contribute to the thickness (diameter) of the plant. This is essential for the plant's structural support and overall growth.

3. **Identifying the Options**:
- **Option 1**: States that secondary tissues add to the length of roots and shoots. This is incorrect as this function is associated with primary meristems.
- **Option 2**: States that secondary tissues add to the diameter of existing roots and shoots. This is correct.
- **Option 3**: States that secondary tissues are found only in the embryo. This is incorrect as secondary tissues develop from primary tissues in mature plants.
- **Option 4**: States that secondary tissues are found only in seedlings. This is also incorrect as secondary tissues develop later in the plant's life cycle.

4. **Conclusion**: Based on the analysis of the options, the correct answer is **Option 2**, which states that secondary tissues add to the diameter of existing roots and shoots.