When a physical ailment has no apparent medical cause, doctors may suspect a disorder?

Color blindness is a recessive trait. the gene for color blindness is on the x chromosome. the family tree below shows the trait of color blindness. the only unknown is the mother in the first generation

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?

Describe the function of the endomembrane system? what organelles are involved?