The primary growth is affected by
(a) Primary cambium
(b) Apical meristems
(c) Cambium
(d) Secondary cambium

Options

A. Primary cambium
B. Apical meristems
C. Cambium
D. Secondary cambium

Answer

To determine which option affects primary growth in plants, let's analyze each option step by step:

1. **Understanding Primary Growth**:
Primary growth refers to the increase in length of the plant, which occurs at the tips of roots and shoots. This growth is primarily due to cell division and elongation.

2. **Identifying Meristems**:
- Meristems are regions of undifferentiated cells in plants that can divide and differentiate into various types of tissues.
- There are two main types of meristems: apical meristems and lateral meristems.

3. **Evaluating the Options**:
- **(a) Primary Cambium**: This is not a standard term used in plant anatomy. Cambium refers to lateral meristems that contribute to secondary growth, not primary growth.
- **(b) Apical Meristems**: These are located at the tips of roots and shoots and are responsible for primary growth by facilitating cell division and elongation. They are crucial for the vertical growth of the plant.
- **(c) Cambium**: This typically refers to the vascular cambium, which is involved in secondary growth, not primary growth.
- **(d) Secondary Cambium**: This term refers to the cambium that contributes to secondary growth, which increases the girth of the plant, not the length.

4. **Conclusion**:
Based on the analysis, the correct answer is **(b) Apical Meristems**, as they are directly responsible for primary growth in plants.

**Final Answer**: (b) Apical meristems