Which of the following is found in seed plants?

Options

A. Complex vascular tissue
B. Pollen grains replace swimming sperm
C. Retention of megagametophyte within the ovule
D. All of the above

Answer

To solve the question "Which of the following is found in seed plants?", we will analyze each option provided and determine their validity in the context of seed plants, specifically angiosperms.

### Step-by-Step Solution:

1. **Understanding Seed Plants**:
- Seed plants include both gymnosperms and angiosperms. Angiosperms are flowering plants that produce seeds enclosed within fruits.

2. **Analyzing Option A: Complex Vascular Tissue**:
- Seed plants possess complex vascular tissues, which include xylem and phloem. This is essential for transporting water, nutrients, and food throughout the plant.
- **Conclusion**: Option A is correct.

3. **Analyzing Option B: Pollen Grains Replace Swimming Sperm**:
- In seed plants, particularly angiosperms, the male gametes (sperm) are carried by pollen grains. Unlike in some non-seed plants where sperm are motile and swim to the egg, in angiosperms, the sperm is non-motile and is delivered via pollen.
- **Conclusion**: Option B is correct.

4. **Analyzing Option C: Retention of Megagametophyte Within the Ovule**:
- In angiosperms, the female gametophyte (megagametophyte) is retained within the ovule. This structure is crucial for fertilization and the development of seeds.
- **Conclusion**: Option C is correct.

5. **Final Conclusion**:
- Since all the options (A, B, and C) are correct, the answer to the question is:
- **Option D: All of the above**.