Lets say that the genotypes are:
Male affected:XbY
Male unaffected: XaY
Female affected: XbXb
Female carrier: XaXb
Female unaffected:XaXa
P: XbY x XaXa
F1: XaXb XaXb XaY XaY The middle square is female carrier.
P:XbY x XaXb
F1: XaXb XbXb XaY XbY The left square is affected female.
P:XaY x XbXb
F1: XaXb XaXb XbY XbY The right square is affected male.
Answer:
Early land animals had both lungs AND gills, and their bodies consisted of few hard parts. Meaning they lacked things like an exoskeleton for instance. Animals today have either lungs OR gills and many have protecting hard parts of their bodies.
Explanation:
Maybe this helps ? Please look at the picture
Two other patterns of inheritance include natural eye color and hair color.
