Intercalary meristems are the primary meristems, because :
I. They appear early in the life of a plant.
II. They contribute to the formation of the primary plant body.

Question

Intercalary meristems are the primary meristems, because :  
I. They appear early in the life of a plant. 
II. They contribute to the formation of the primary plant body.

Accepted Answer

Intercalary meristems are indeed classified as primary meristems, and Option 1 is the correct answer because both statements I and II are accurate. Let's delve into the reasons why:

1. **Explanation for Statement I: "They appear early in the life of a plant."**
   - Intercalary meristems are found in certain plants, particularly grasses and other monocots. These meristems are located at the base of leaves or internodes and are responsible for the elongation of these parts. They appear early in the plant's life cycle, during the initial stages of growth. This early appearance is characteristic of primary meristems, which are involved in the primary growth of the plant, contributing to the increase in length.

2. **Explanation for Statement II: "They contribute to the formation of the primary plant body."**
   - The primary plant body is formed through the activity of primary meristems, which include apical meristems and intercalary meristems. Intercalary meristems contribute to the elongation of stems and leaves, which are integral parts of the primary plant body. This growth is essential for the plant to reach its mature form and function effectively in its environment.

Now, let's examine why the other options are incorrect:

- **Option 2: Both I and II are incorrect**
  - This option is incorrect because both statements I and II are true. Intercalary meristems do appear early in the plant's life and do contribute to the formation of the primary plant body, as explained above.

- **Option 3: Only I is correct**
  - This option is incorrect because it dismisses the truth of statement II. As established, intercalary meristems do contribute to the formation of the primary plant body, making statement II correct as well.

- **Option 4: Only II is correct**
  - This option is incorrect because it dismisses the truth of statement I. Intercalary meristems do appear early in the life of a plant, making statement I correct as well.

In conclusion, both statements I and II accurately describe the characteristics and functions of intercalary meristems, justifying why Option 1 is the correct answer.