In echinoderms, the fertilization is

Options

A. internal
B. External
C. In a cocoon
D. All of these

Answer

### Step-by-Step Solution:

1. **Identify the Type of Organism**: Echinoderms are a group of marine animals that include starfish, sea urchins, and sea cucumbers. They are characterized by their radial symmetry and a water vascular system.

2. **Understand the Reproductive System**: Echinoderms are dioecious, meaning that there are distinct male and female individuals. This is an important characteristic as it influences how fertilization occurs.

3. **Fertilization Process**: In Echinoderms, fertilization occurs externally. This means that males and females release their gametes (sperms and eggs) into the surrounding water.

4. **Gamete Release**: Males release sperm into the water, and females release eggs. The gametes then meet in the water, and fertilization occurs outside of the bodies of the organisms.

5. **Development**: After fertilization, the zygotes develop into larvae, which eventually grow into adult Echinoderms. This external fertilization is typical for many marine organisms.

6. **Conclusion**: Therefore, the correct answer to the question about fertilization in Echinoderms is that it is external.

### Final Answer:
In Echinoderms, the fertilization is external.

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