Final answer:
An individual with Klinefelter syndrome has a sex chromosome composition of XXY. This condition occurs in males and is characterized by small testes, enlarged breasts, and reduced body hair.
Step-by-step explanation:
An individual with Klinefelter syndrome has a sex chromosome composition of XXY. Klinefelter syndrome is a condition where a male individual has an extra X chromosome, resulting in small testes, enlarged breasts, and reduced body hair. In all types of Klinefelter syndrome, every X chromosome except one undergoes inactivation to compensate for the excess genetic dosage, which can be seen as several Barr bodies in each cell nucleus.