Coevolution does not occur in case of

Options

A. Parasitism
B. Mutualism
C. both A and B
D. Commensalism

Answer

### Step-by-Step Solution:

1. **Understanding Coevolution**:
Coevolution is a process where two or more species influence each other's evolutionary trajectory through their interactions. This can include various forms of relationships, such as mutualism, parasitism, and predation.

2. **Identifying Types of Interactions**:
- **Mutualism**: Both species benefit from the interaction.
- **Parasitism**: One species benefits at the expense of the other.
- **Predation**: One species (the predator) benefits by consuming another (the prey).
- **Commensalism**: One species benefits while the other is neither helped nor harmed.

3. **Analyzing the Question**:
The question asks for a scenario where coevolution does not occur. In coevolution, there must be a significant interaction between species that leads to evolutionary changes.

4. **Identifying the Correct Answer**:
Commensalism is the interaction where one species benefits and the other is unaffected. Since there is no significant impact on the other species, coevolution does not occur in this case.

5. **Conclusion**:
Therefore, the answer to the question is that coevolution does not occur in the case of **commensalism**.