Polar molecules occur when there is an electronegativity difference between the bonded atoms. Nonpolar molecules occur when electrons are shared equal between atoms of a diatomic molecule or when polar bonds in a larger molecule cancel each other out
In the graph you can so that two of the shapes ae fully black, that means that they are color blind, the half colored ones means they are a carrier but they aren't color blind. So two males in the offspring are color blind.