A molecule that elicits an immune response is called

Options

A. Antigen
B. Antibody
C. Carcinogen
D. Mutagen

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the name of a molecule that triggers an immune response in the body.

2. **Identifying Key Terms**: The key term here is "immune response." This refers to the body's defense mechanism against foreign substances.

3. **Analyzing the Options**:
- **Antigen**: A substance that induces an immune response, typically recognized by the immune system as foreign.
- **Antibody**: A protein produced by the immune system in response to an antigen.
- **Carcinogen**: A substance that can lead to cancer.
- **Mutagen**: An agent that causes changes or mutations in the DNA.

4. **Evaluating Each Option**:
- **Antigen**: This is the correct answer as it directly refers to a molecule that elicits an immune response.
- **Antibody**: This option is incorrect because antibodies are produced in response to antigens, not the other way around.
- **Carcinogen**: This option is incorrect as it refers to substances that cause cancer, not immune responses.
- **Mutagen**: This option is incorrect because mutagens cause genetic mutations, not immune responses.

5. **Conclusion**: The correct answer is **Antigen** as it is the molecule that elicits an immune response.

**Final Answer**: A molecule that elicits an immune response is called an **Antigen**.

---