Final answer:
A Klinefelter (XXY) cat cannot exhibit tortoiseshell color because tortoiseshell coloring is the result of two different X chromosomes with different coat color alleles undergoing random inactivation in females. Klinefelter syndrome results in a male phenotype with an extra X chromosome, but these males do not show the tortoiseshell pattern.
Step-by-step explanation:
The answer to the student's question is false, a Klinefelter (XXY) cat cannot have a tortoiseshell color. Tortoiseshell coat color in cats is a result of embryonic X inactivation, which is observed in mammalian females who have two different X chromosomes that carry different alleles for coat color.
Since male cats have only one X chromosome, under normal circumstances they do not exhibit a tortoiseshell coat. The XXY genotype corresponds to Klinefelter syndrome, which typically results in a male phenotype. While males with Klinefelter syndrome have an extra X chromosome, the presence of a Y chromosome results in a male phenotype, and they do not express the tortoiseshell pattern because it requires two X chromosomes with different coat color alleles to be randomly inactivated between different cells during development.