Presence of two chambered heart and gills in tadpole is example of

Options

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

Answer

To answer the question regarding the presence of a two-chambered heart and gills in tadpoles, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Organism**: The question mentions a tadpole, which is the larval stage of amphibians, specifically frogs.

2. **Examine the Characteristics**: The tadpole has a two-chambered heart and gills. These features are typical of fish (Pisces), as adult amphibians usually have a three-chambered heart and lungs for breathing air.

3. **Understand Evolutionary Relationships**: Amphibians, including frogs, evolved from fish. This means that certain ancestral traits can still be present in their larval forms, such as the tadpole.

4. **Define Atavism**: Atavism refers to the reappearance of ancestral traits in a descendant that were lost in previous generations. In this case, the presence of a two-chambered heart and gills in the tadpole is a reappearance of traits that are characteristic of its fish ancestors.

5. **Evaluate the Options**:
- Radiation: This refers to a type of evolutionary diversification, not applicable here.
- Atavism: This fits the description as it involves the reappearance of ancestral traits.
- Mutation: This refers to changes in DNA, not directly related to the presence of ancestral traits.
- Crossing Over: This is a genetic process during meiosis, not relevant to the presence of gills and a two-chambered heart in tadpoles.

6. **Conclusion**: Based on the analysis, the correct answer is atavism, as the tadpole exhibits ancestral characteristics that are not present in the adult form of the amphibian.

### Final Answer:
The presence of a two-chambered heart and gills in tadpole is an example of **atavism**.