Fitness of one species is significantly lower in the presence of another species in case of

Options

A. Predation
B. Parasitism
C. Competition
D. Mutualism

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about a scenario where the fitness of one species is significantly lower due to the presence of another species.

2. **Analyzing the Options**:
- **Option A: Predation**: In predation, one species (the predator) benefits at the expense of another (the prey). While this affects the prey's fitness, it does not fit the definition of both species being negatively impacted.
- **Option B: Parasitism**: In parasitism, one species (the parasite) benefits while the other (the host) is harmed. This again does not describe a situation where both species are negatively impacted.
- **Option C: Competition**: Competition occurs when two species vie for the same resources (like food, space, etc.), leading to a situation where the presence of one species lowers the fitness of the other. This fits the question perfectly.
- **Option D: Mutualism**: Mutualism is a relationship where both species benefit from the interaction, which contradicts the premise of the question.

3. **Conclusion**: Based on the analysis, the correct answer is **Option C: Competition**, as it directly describes a scenario where the fitness of one species is significantly lower in the presence of another species.

### Final Answer:
**C: Competition**

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