A somatic cell of an animal has 18 chromosomes.
What is the diploid number of chromosomes for this animal?

Answer

To determine the diploid number of chromosomes for the animal in question, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of Somatic Cells**: Somatic cells are the body cells that are not involved in reproduction. They undergo mitosis and contain the diploid number of chromosomes.

2. **Identify the Given Information**: The problem states that a somatic cell of the animal has 18 chromosomes.

3. **Recognize the Diploid Number**: The diploid number of chromosomes is represented as 2N, where N is the number of chromosomes in a haploid cell (gametes). In somatic cells, the diploid number is double that of the haploid number.

4. **Calculate the Diploid Number**: Since the somatic cell has 18 chromosomes, this means that the diploid number (2N) is 18. Therefore, the haploid number (N) would be half of that, which is 9. However, since the question asks for the diploid number, we can state that the diploid number is 18.

5. **Conclusion**: The diploid number of chromosomes for this animal is 18.

### Final Answer:
The diploid number of chromosomes for this animal is **18**.

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