the results of thomas hunt morgans last cross are shown in the punnett square below. which of thomas hunt…

Brief Explanations:

In the Punnett - square, there are no female flies with white - eye genotypes that are absent, but male flies with only the recessive white - eye allele on the X - chromosome are present. If white eyes were lethal in female Drosophila, we would not see the $X^{R}X^{r}$ genotypes in females. Since we see male flies with white eyes ($X^{r}Y$) and no indication of lethality in females with the appropriate genotypes, white eyes are not lethal in female Drosophila. And the presence of male flies with white eyes ($X^{r}Y$) does not suggest that white eyes are lethal in male Drosophila either as they are present in the cross results. However, if we consider the context of Morgan's work on sex - linked inheritance, the fact that the trait is associated with the sex chromosomes is more relevant. But among the given options, since there are no missing female genotypes related to white eyes, white eyes are not lethal in female Drosophila.

Answer:

White eyes are lethal in female Drosophila. (This answer is incorrect among the given options based on the Punnett - square analysis, but it seems to be a mis - phrased question as the correct conclusion from the Punnett - square is that white eyes are not lethal in either sex among the given options. If we assume we are choosing the least wrong option based on the analysis of the genotypes in the Punnett - square, we would note that the absence of female white - eyed genotypes would be expected if white eyes were lethal in females, and that's not the case here.)