Selelct one of the following paris of important features distinguishig Gnetum from Cycas and Pinus and showing affinities with angiosperms

Options

A. perianth and two integuments
B. embryo development and apical meristem
C. absence of resin duct and leaf venation
D. presence of vessel elements and absence of Archegonia

Answer

To solve the question regarding the distinguishing features of Gnetum compared to Cycas and Pinus, and how these features show affinities with angiosperms, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Groups**:
- Gnetum is part of the Gnetophyta division, which is known for having some angiosperm-like characteristics.
- Cycas belongs to the Cycadophyta division, and Pinus is part of the Pinophyta division (conifers).

2. **Identifying Key Features**:
- We need to identify features that are unique to Gnetum and also show similarities with angiosperms, while being different from Cycas and Pinus.

3. **Analyzing the Options**:
- **Option A**: Presence of two integuments - This is a feature of angiosperms, but not unique to Gnetum when compared to Cycas and Pinus.
- **Option B**: Embryo development and apical meristem, absence of bracteoles, and leaf venation - This option is too broad and does not distinctly separate Gnetum from the other two.
- **Option C**: Presence of vessels - Gnetum has vessel elements, while Cycas and Pinus do not. This is a significant distinguishing feature.
- **Option D**: Presence of basal elements and absence of archegonia - This option is also relevant as Gnetum does not have archegonia, unlike Cycas.

4. **Selecting the Correct Option**:
- After analyzing the options, **Option D** is the correct choice as it highlights the presence of basal elements and absence of archegonia, which are features that distinguish Gnetum from Cycas and Pinus and show its affinity with angiosperms.

### Final Answer:
The correct answer is **Option D: Presence of basal elements and absence of archegonia**.