He family tree below shows the trait of color blindness. the only unknown is the father in the first generation. what must be true about the father?

Ineed to know why d is the correct answer asap

In many humans, exposing the skin to sunlight over prolonged periods of time results in the production of more pigment by the skin cells (tanning). this change in skin color provides evidence that -

Why do some dna fragments move farther than others during gel electrophoresis? a. because their shapes are different b. because they are different types of molecules c. because the samples are different colors d. because their masses are different