Question

which of thomas hunt morgans hypotheses was valid based on these results?
white eyes are lethal in female drosophila.
white eyes are lethal in male drosophila.
female drosophila with white eyes are homozygous recessive.
white eyes are the dominant trait in female drosophila.

Explanation:

Thomas Hunt Morgan studied eye - color inheritance in Drosophila. In the Punnett - square shown, white - eyed females are not present. White - eyed females would be $X^{r}X^{r}$. Since they are not present, it implies that female Drosophila with white eyes are homozygous recessive and likely have some associated factor that affects their viability or presence in the observed population. White eyes are not lethal in males as $X^{r}Y$ males are present. There is no evidence to suggest white eyes are lethal in females or that white eyes are dominant in females.

Answer:

Female Drosophila with white eyes are homozygous recessive.