The only taxon that exists in nature in which exchange of gene takes place is

Options

A. species
B. genus
C. phylum or division
D. kingdom

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about a taxon in which gene exchange occurs in nature. A taxon refers to a group of one or more populations of organisms that form a unit.

2. **Identifying Taxonomic Levels**: In biological classification, there are several hierarchical levels: Kingdom, Phylum (or Division), Class, Order, Family, Genus, and Species. Each level has a different number of organisms and shared characteristics.

3. **Analyzing Gene Exchange**: Gene exchange typically occurs during reproduction. In biological terms, this exchange is most commonly observed within a species. Members of the same species can interbreed and produce fertile offspring, allowing for the exchange of genetic material.

4. **Example of Species**: To illustrate, consider the species *Mangifera indica*, which is the mango. Two individuals of this species can reproduce with each other, allowing for gene exchange through sexual reproduction.

5. **Comparing Higher Taxa**: If we look at higher taxonomic levels, such as genus (e.g., *Equus* for horses and zebras), individuals from different species within the same genus cannot typically interbreed successfully. This indicates that gene exchange does not occur at these higher levels.

6. **Conclusion**: Based on the analysis, the only taxon in which gene exchange occurs is the species level. Therefore, the correct answer to the question is "species."

### Final Answer:
The only taxon that exists in nature in which exchange of genes takes place is **species**.

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