Which of the following characters represents the affinities of Gnetum with angiosperms and differences with Cycas and Pinus?

Options

A. presence of xylem vessel and absence of archegonia
B. perianth and two integuments
C. embryo development and apical meristem
D. Absence of resin ducts and leaf venation

Explanation

To determine the characters that represent the affinities of Gnetum with angiosperms and the differences with Cycas and Pinus, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Organism**: Gnetum is a member of the Gymnosperms, which are seed-producing plants that do not form flowers or fruits.

2. **Understand the Characteristics of Angiosperms**: Angiosperms, or flowering plants, are characterized by the presence of flowers, fruits, and xylem vessels. They also typically have broad leaves with reticulate venation.

3. **Compare Gnetum with Cycas and Pinus**:
- **Cycas**: This is a type of cycad, which has characteristics such as the presence of archegonia (female reproductive structures) and lacks xylem vessels.
- **Pinus**: This is a conifer, which also has archegonia and typically lacks xylem vessels in the same way that angiosperms do.

4. **Identify Similarities of Gnetum with Angiosperms**:
- **Presence of Xylem Vessels**: Gnetum has xylem vessels, which is a characteristic shared with angiosperms.
- **Absence of Archegonia**: Unlike Cycas and Pinus, Gnetum does not have archegonia, which is another feature that aligns it more closely with angiosperms.

5. **Summarize the Key Points**:
- Gnetum shows affinities with angiosperms through the presence of xylem vessels and the absence of archegonia.
- These characteristics differentiate it from Cycas and Pinus, which possess archegonia and lack xylem vessels.

### Conclusion:
The characters that represent the affinities of Gnetum with angiosperms and differences with Cycas and Pinus are the **presence of xylem vessels** and the **absence of archegonia**.

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