Based on this information, what is Sugar's phenotype for the fur texture trait?

 - straight fur
 - wavy fur
Sugar's genotype for the fur texture gene is ff. Sugar's genotype of ff has only f alleles. The f allele is for wavy fur. So, Sugar's phenotype for the fur texture trait must be wavy fur.
To check this answer, consider whether Sugar's alleles are dominant or recessive. The allele for wavy fur (f) is recessive to the allele for straight fur (F). This means F is a dominant allele, and f is a recessive allele.
Sugar's genotype of ff has only recessive alleles. An organism with only recessive alleles for a gene will have the recessive allele's version of the trait. So, Sugar's phenotype for the fur texture trait must be wavy fur.