Thr fertilization in majority of echinoderms occurs in open water.

Answer

**Step-by-Step Solution:**

1. **Understanding Echinoderms**: Echinoderms are a group of marine animals that include starfish, sea urchins, and sea cucumbers. They belong to the phylum Echinodermata.

2. **Reproductive Process**: In most echinoderms, reproduction occurs through a process known as external fertilization. This means that the sperm and eggs are released into the open water, rather than being fertilized inside the body.

3. **Mechanism of Fertilization**: During external fertilization, male echinoderms release sperm into the water, while female echinoderms release eggs. The sperm then swim through the water to fertilize the eggs.

4. **Formation of Zygote**: Once the sperm successfully fertilizes the egg, a zygote is formed. This zygote will then develop into a larval stage before maturing into an adult echinoderm.

5. **Conclusion**: Therefore, the statement that "fertilization in the majority of echinoderms occurs in open water" is true, as it accurately describes the external fertilization process that is common among these organisms.