Which individuals showing the dominant phenotype could possibly be either homozygous or heterozygous?

Either could be heterozygous or homozygous, as the dominant will show and the recessive won't in both cases. Unless, of course, the individual has two dominant trait, in which case they would show both.

This is what i did 45-5=4040÷4=10so there are 10 white marbles but am not sure is just a question that am not sure