Which conclusion about the meaning of y is correct if the allele combination yy is for yellow seeds?
yellow and dominant
green and recessive
yellow and recessive
green and dominant

The answer is yellow and dominant.

We have two alleles, one dominant and one recessive: Y and y. Usually, a capital letter is used for dominant alleles, so Y is a dominant allele and y is a recessive allele. There are three combinations of those alleles, and thus, three genotypes: YY, Yy, yy.
We know that Yy is for yellow seeds. An individual with Yy is heterozygote. Heterozygotes have one dominant and one recessive allele, but the dominant masks the recessive allele, so expressed trait is dominant. Since yellow seed is the result of heterozygous Yy, yellow seed is the dominant trait.
Therefore, Y means yellow and dominant.