The skin's dermis is made of layers of cells, connective tissue and several structures that aid in maintaining its function. These structures include blood vessels, hair follicles, lymph vessels and glands.
XnY one color blind boy. 1  Probability of having a color blind daughter is (1/2 x 1/2) or 1/4 or 25% (0.25) This is because both sex and colorblindness are involved in the solution.  The probability that their first son is color blind is 50% (0.50). In this question only males are part of the solution.
For example, if your uncle married a woman who carried the color blind gene, then each of their sons and daughters would have a 50% chance of being color blind. In this case, it would look like the man, your uncle, passed his colorblindness down to his kids.