Polytene chromosome occur in cells of salivary glands of

Options

A. Some insects
B. Rabbit
C. Humans
D. Mice

Answer

**Step-by-Step Solution:**

1. **Understanding Polytene Chromosomes**: Polytene chromosomes are a type of chromosome that is characterized by being much larger than typical chromosomes. They are formed by the replication of DNA without cell division, leading to many identical strands of DNA lying side by side.

2. **Location of Polytene Chromosomes**: These chromosomes are primarily found in the salivary glands of certain organisms. The salivary gland cells of these organisms undergo a specific type of DNA replication that results in the formation of polytene chromosomes.

3. **Identifying the Organisms**: The question mentions several organisms: insects, rabbits, humans, and mice. Among these, polytene chromosomes are specifically known to occur in the salivary glands of certain insects.

4. **Examples of Insects**: A well-known example of insects that have polytene chromosomes is the fruit fly (Drosophila melanogaster). The salivary glands of the larvae of these flies are particularly studied for their polytene chromosomes.

5. **Conclusion**: Based on the information, the correct answer to the question is that polytene chromosomes occur in the cells of salivary glands of insects, specifically in the larvae of certain flies like fruit flies.

**Final Answer**: Polytene chromosomes occur in cells of salivary glands of insects (e.g., fruit flies).

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