The biological definition of a species depends on

Options

A. the geographical distribution of two groups of organisms
B. reproductive isolation of two groups of organisms
C. anatomical and developmental differences between the two groups of organisms
D. difference in the adaptation of two groups of organisms

Answer

To answer the question regarding the biological definition of a species, we can break down the solution into the following steps:

### Step-by-Step Solution:

1. **Understanding the Concept of Species**:
- A species is defined as a group of closely related organisms that share similar characteristics.

2. **Interbreeding Capability**:
- One of the key criteria for defining a species is that the organisms within that group must be capable of interbreeding. This means they can mate and produce offspring.

3. **Fertility of Offspring**:
- Not only must the organisms be able to interbreed, but the offspring produced must also be fertile. This ensures that the species can continue to reproduce and maintain its population.

4. **Reproductive Isolation**:
- Reproductive isolation is a crucial factor in defining a species. It refers to the inability of different species to breed with one another, which helps maintain distinct species boundaries.

5. **Evaluating Options**:
- When considering the options provided in the question, we need to identify which one aligns with the biological definition of a species.
- The options include:
- Geographical distribution
- Reproductive isolation
- Anatomical and developmental differences
- Differences in adaptation

6. **Identifying the Correct Option**:
- The option that best fits the biological definition of a species is "reproductive isolation of two groups of organisms." This is because the ability to interbreed and produce fertile offspring is central to the definition of a species.

7. **Conclusion**:
- Therefore, the biological definition of a species primarily depends on reproductive isolation and the ability of organisms to interbreed and produce fertile offspring.

### Final Answer:
The biological definition of a species depends on the reproductive isolation of two groups of organisms.

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