Final answer:
If a mutation appears in a cell, only the progeny of that cell will be affected in the individual where the mutation occurs. Whether the mutation can be passed on to future generations depends on whether it occurred in a germ cell or a somatic cell.
Step-by-step explanation:
When a mutation appears in a cell, only the progeny (offspring) of that cell will be affected in the individual in which the mutation occurs. However, whether the mutation can be passed on to future generations depends on whether the mutation occurred in a germ cell or a somatic cell.
A mutation in a germ cell, such as a sperm or egg, can be passed on to offspring. In this case, all cells of the offspring will have the mutation. This is how hereditary diseases are inherited.
On the other hand, a mutation in a somatic cell, which is any cell other than a germ cell, will only affect the progeny (descendant) cells of that particular somatic cell. It will not be passed on to offspring.