7. Explain the difference between disorders of chromosome number and disorders caused by individual genes

A person can have normal chromosomes in number and structure, but still have a disease or condition caused by a mutation in one or more of the genes on the chromosomes. A single gene defect usually does not cause the chromosome structure or number to be abnormal.

Explanation:

I'm not sure if this is correct but hope it helps.

a unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring.