Conifers differ from grasses in the

Options

A. absence of pollen tubes
B. formation of endosperm before fetili-zation
C. production of seeds from ovules
D. lack of xylem tracheids

Answer

To answer the question regarding how conifers differ from grasses, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Groups**:
- Conifers are classified as gymnosperms, while grasses are classified as angiosperms.

2. **Understand Endosperm Formation**:
- In conifers (gymnosperms), the endosperm is formed before fertilization. This means that the nutritive tissue that will support the developing embryo is already present when fertilization occurs.
- In contrast, in grasses (angiosperms), the endosperm is formed after fertilization. The fertilized ovule develops into a seed, and then the endosperm is formed to nourish the embryo.

3. **Evaluate Other Options**:
- **Option A (absence of pollen tubes)**: Both conifers and grasses produce pollen tubes for fertilization.
- **Option C (production of seed from ovules)**: Both groups produce seeds from ovules.
- **Option D (lack of xylem tracheids)**: Both conifers and grasses have xylem tracheids, although their structure and function may differ.

4. **Conclusion**:
- The main difference between conifers and grasses, based on the options provided, is the formation of endosperm. Therefore, the correct answer is **Option B: formation of endosperm before fertilization**.

### Final Answer:
Conifers differ from grasses in the formation of endosperm before fertilization (Option B).

---