The embryos of fish, chickens and pigs have gill slits and a tail. The presence of these features suggests that

Options

A. all these animals can swim.
B. these animals may have had a common ancestor.
C. gill slits and tails are required for embryonic development.
D. pigs developed from chickens.

Explanation

**Step-by-Step Solution:**

1. **Observation of Embryonic Features**: The embryos of fish, chickens, and pigs exhibit certain common features, specifically gill slits and a tail.

2. **Understanding Gill Slits and Tails**: Gill slits are structures that are present in the early stages of development in various vertebrates. They are associated with the respiratory system in aquatic animals and are a part of the embryonic development process.

3. **Comparative Anatomy**: The presence of these features in different species suggests a similarity in their developmental processes. This is a key concept in evolutionary biology, where similar embryonic features indicate a commonality in evolutionary ancestry.

4. **Common Ancestry vs. Developmental Needs**: While it might be tempting to conclude that these animals share a common ancestor, it is more accurate to say that the presence of gill slits and tails is a requirement for embryonic development rather than a direct indication of a shared lineage.

5. **Conclusion**: Therefore, the presence of gill slits and tails in the embryos of fish, chickens, and pigs suggests that these features are necessary for their embryonic development.

**Final Answer**: The presence of gill slits and a tail in the embryos of fish, chickens, and pigs suggests that these features are required for embryonic development.

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