Animals exhibiting external fertilisation produce a large number of gametes. Pick the appropriate reason from the following

Options

A. The animals are small in size and want to produce more offsprings.
B. Food is available in plenty in water
C. To ensure better chance of fertilisation.
D. Water promotes production of large number of gametes

Answer

**Step-by-Step Solution:**

1. **Understanding External Fertilization:**
- External fertilization occurs when the male and female gametes unite outside the female's body. This is common in aquatic animals like fish and amphibians.

2. **Reason for Producing a Large Number of Gametes:**
- Since fertilization happens outside the body, the chances of the gametes meeting and successfully fertilizing each other are relatively low. To increase the likelihood of successful fertilization, animals that reproduce through external fertilization release a large number of gametes.

3. **Evaluating the Options:**
- **Option 1:** "Animals are small in size and want to produce more offspring."
- This is incorrect because the size of the animal does not directly correlate with the number of gametes produced.

- **Option 2:** "Food is available in plenty of water."
- This is also incorrect. The availability of food does not influence the number of gametes produced for fertilization.

- **Option 3:** "To ensure better chance of fertilization."
- This is the correct option. By producing a large number of gametes, animals increase the chances that some will successfully fertilize.

- **Option 4:** "Water promotes production of a large number of gametes."
- This is incorrect as water is merely the medium for fertilization and does not promote the production of gametes.

4. **Conclusion:**
- The most appropriate reason for animals exhibiting external fertilization to produce a large number of gametes is to ensure a better chance of fertilization.

**Final Answer:**
- The correct reason is: "To ensure better chance of fertilization."

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