Study of impact of extra-terrestrial environments on organisms belonging to earth is component of

Options

A. Ecology
B. Cosmology
C. Exobiology
D. Ethnology.

Answer

To solve the question regarding the study of the impact of extra-terrestrial environments on organisms belonging to Earth, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the field of study that focuses on how extra-terrestrial environments affect organisms on Earth.

2. **Identifying Key Terms**: The key terms in the question are "extra-terrestrial environments" and "organisms belonging to Earth." This indicates that we are looking for a scientific discipline that studies the interaction between space environments and Earth life.

3. **Evaluating the Options**:
- **Ecology**: This is the study of interactions between organisms and their environment, but it typically focuses on Earth.
- **Cosmology**: This is the study of the universe as a whole, including its origins and evolution, but does not specifically focus on organisms.
- **Exobiology**: This is the branch of biology that studies the possibility of life beyond Earth and the effects of extra-terrestrial environments on Earth organisms.
- **Ethnology**: This is the comparative and analytical study of cultures, which is not relevant to the question.

4. **Selecting the Correct Option**: Based on the definitions and focus areas of each option, **Exobiology** is the correct answer, as it specifically deals with the impact of extra-terrestrial environments on organisms from Earth.

5. **Conclusion**: Therefore, the study of the impact of extra-terrestrial environments on organisms belonging to Earth is a component of **Exobiology**.

### Final Answer:
The correct option is **Exobiology**.