Frank and Maria both had normal vision. After they married, they had two daughters and a son. Both daughters had normal vision and never had children. Marco, the son, was color blind. He married Lauren, who had normal vision. Marco and Lauren had two children, Caleb and Molly. Caleb was not color blind, but Molly was. Color blindness is a sex-linked trait (carried on the X chromosome). The diagram below shows the family tree. Which statement about this family's pedigree is correct? Marco carried the gene for color blindness, but Lauren did not. Lauren carried the gene for color blindness, but Marco did not. Marco and Lauren both carried genes for color blindness. Frank and Caleb both carried genes for color blindness.

the answer is : Marco carry the gene for color blindness, but Lauren did not.

Color blindness is a usually a genetic (hereditary) condition (you are born with it). Red/green and blue color blindness is usually passed down from your parents. The gene which is responsible for the condition is carried on the X chromosome and this is the reason why many more men are affected than women. as man has a 2 chromosomes X and Y, so both the chromosome can be transfered into the baby as the coming gene normally carry the men's heridity. The effects of color vision deficiency can be mild, moderate or severe depending upon the defect. If you have inherited color blindness your condition will stay the same throughout your life - it won't get any better or worse. People with normal color vision have all three types of cone/pathway working correctly but color blindness occurs when one or more of the cone types are faulty. For example, if the red cone is faulty you won't be able to see colors containing red clearly. Most people with color blindness can't distinguish certain shades of red and green. That's why this comes into the gene once in the generation.

the answer is A. on e2020