Define external fertilisation. Mention its disadvantages.

Explanation

**Step-by-Step Text Solution:**

1. **Definition of External Fertilization:**
- External fertilization is a reproductive process where the fusion of male and female gametes occurs outside the female's body. This typically takes place in an external medium, which is usually water.

2. **Examples of Organisms:**
- Common examples of organisms that utilize external fertilization include fish, frogs, and starfish.

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