Homozygous means that both alleles (I and i are the alleles) are the same. You're given that I is dominant over i, so I is the dominant allele and i is the recessive allele. So organisms that are II and ii are homozygous. II is homozygous dominant while ii is homozygous recessive.
Heterozygeous, on the other hand, means that both alleles are different. In this case, Ii would be heterozygous.
To do this cross, write down the allele from each row and column in the box where they meet. Usually the dominant allele goes first if it's heterozygous. Select the box where you have two dominant alleles (II).
You should be selecting the bottom left box.
