The population interactions in which one organism is harmed and the other is not affected and is widely used in medical science for the action of antibiotics is

Options

A. Commensalism
B. Parasitism
C. Mutualism
D. Amensalism

Answer

To solve the question regarding the population interactions where one organism is harmed while the other is unaffected, we can analyze the options provided step by step.

### Step 1: Understand the Definitions of Each Interaction
- **Commensalism**: This interaction involves one species benefiting while the other is neither helped nor harmed. It can be represented as (+, 0).
- **Parasitism**: In this interaction, one organism (the parasite) benefits at the expense of the other (the host), which is harmed. This can be represented as (+, -).
- **Mutualism**: Both species benefit from this interaction, represented as (+, +).
- **Amoncellism**: This is not a standard term in ecology, but based on the context, it seems to refer to a scenario where one species is harmed while the other is unaffected, represented as (-, 0).

### Step 2: Analyze Each Option
1. **Commensalism**: This is incorrect because it does not involve harm to one of the species.
2. **Parasitism**: This is incorrect because it involves one species benefiting while the other is harmed, but it does not fit the criteria of one being unaffected.
3. **Mutualism**: This is incorrect as both species benefit, which does not fit the requirement of one being harmed.
4. **Amoncellism**: This is the correct answer as it describes the interaction where one organism is harmed and the other is unaffected.

### Conclusion
The correct answer is **Amoncellism**, where one organism is harmed and the other is unaffected. This interaction is relevant in medical science, especially in the context of antibiotics, as antibiotics can harm bacteria (the target) while not affecting the host organism.