Step-by-step explanation:
No, I do not agree with the student's statement that the genotype of the Drosophila must be homozygous just based on the observation of red eyes. In Drosophila genetics, eye color is determined by multiple genes and is a polygenic trait. Red eye color can be the result of different genotypes, including homozygous and heterozygous combinations.
If the student had observed white eyes, which is a recessive trait, then we could assume homozygosity as the genotype must contain the recessive allele for white eye color. However, in the case of red eyes, it is not possible to determine the genotype solely based on this observable characteristic. Additional genetic crosses or tests would be needed to accurately determine the genotype of the Drosophila.