Why are men the colorblind ones? (Vertical Integration Part 1: Biology)

In school, you learn one field at a time (bio, chem, etc.), but you need every field for true understanding. So let’s answer one question with EVERY field: why are men often colorblind?
Part I explores the biology of red-green colorblindness. … More Why are men the colorblind ones? (Vertical Integration Part 1: Biology)