Theory of heterogametes for sex determination was proposed by

Options

A. Morgan
B. Darwin
C. Correns
D. Bridges

Answer

To solve the question regarding who proposed the theory of heterogametes for sex determination, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Heterogametes**:
- Heterogametes refer to the different types of gametes produced by different sexes. In many species, males and females produce different gametes that determine their sex.

2. **Identify the Gametes in Humans**:
- In humans, males produce two types of gametes: X and Y. Females produce only one type of gamete: X. This difference in gametes is crucial for determining the sex of the offspring.

3. **Review the Options Provided**:
- The options given are: Morgan, Darwin, Collins, and Bridges. We need to evaluate each option based on their contributions to genetics.

4. **Evaluate Each Scientist**:
- **Morgan**: Known for his work on genetic linkage, not for the theory of heterogametes.
- **Darwin**: Famous for the theory of natural selection, not related to sex determination.
- **Collins**: This is the correct answer as he proposed the theory of heterogametes for sex determination.
- **Bridges**: Known for his work on non-disjunction phenomena in genetics, not for the theory of heterogametes.

5. **Conclusion**:
- After evaluating the contributions of each scientist, the correct answer to the question is **Collins**.

### Final Answer:
The theory of heterogametes for sex determination was proposed by **Collins**.

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