Presence of tail and coarse hair in human baby is

Options

A. Radiation
B. Atavism
C. Mutation
D. Crossing over

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the presence of a tail and coarse hair in a human baby. We need to identify what this phenomenon is called in biological terms.

2. **Identifying Key Terms**: The terms "tail" and "coarse hair" suggest that these features are not typical in modern humans but may have been present in ancestral species.

3. **Defining Atavism**: Atavism refers to the reappearance of traits or characteristics that were present in distant ancestors but have been absent in more recent generations. This can include physical features that are not common in the species today.

4. **Examples of Atavism**: The transcript mentions an example of atavism where a descendant exhibits a trait (like blue eyes) that was present in a distant ancestor but not in the immediate lineage. Similarly, the presence of a tail and coarse hair in a human baby can be seen as a reversion to ancestral traits.

5. **Conclusion**: Based on the definition and understanding of atavism, the presence of a tail and coarse hair in a human baby is best described as atavism.

**Final Answer**: The presence of a tail and coarse hair in a human baby is an example of atavism.

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