Based on this information, what is this fly's phenotype for the eye color trait?

 - brown eyes
 - red eyes
The fruit fly's genotype for the eye color gene is ee. The fruit fly's genotype of ee has only e alleles. The e allele is for brown eyes. So, the fruit fly's phenotype for the eye color trait must be brown eyes.
To check this answer, consider whether the fruit fly's alleles are dominant or recessive. The allele for red eyes (E) is dominant over the allele for brown eyes (e). This means E is a dominant allele, and e is a recessive allele.
The fruit fly's genotype of ee has only recessive alleles. An organism with only recessive alleles for a gene will have the recessive allele's version of the trait. So, the fruit fly's phenotype for the eye color trait must be brown eyes.