To determine the number of chromosomes in a gamete from a typical organism, we need to understand the relationship between somatic cells (like muscle cells) and gametes in terms of chromosome count.
Here is the step-by-step solution:
1. A muscle cell is a type of somatic cell, which means it contains the full set of chromosomes typical for that organism.
2. In this case, the muscle cell has 40 chromosomes.
3. Gametes (sperm or eggs) are different from somatic cells because they contain half the number of chromosomes. This is due to the process of meiosis, where a cell divides to produce gametes, each with half the chromosome number of the original somatic cell.
4. To find the number of chromosomes in a gamete, we divide the number of chromosomes in the somatic cell by 2.
5. Thus, the number of chromosomes in a gamete is:
\(\[
\text{Number of chromosomes in a gamete} = \frac{\text{Number of chromosomes in a muscle cell}}{2} = \frac{40}{2} = 20
\]\)
So, the correct answer is:
20
