Question

why are white - eyed female fruit flies so rare in nature?
white - eyed females are not rare.
the allele for white eyes was nearly removed from the gene pool.
females must inherit two copies of the recessive allele.

Explanation:

In fruit flies, eye - color is a sex - linked trait. The gene for eye - color is located on the X chromosome. Females have two X chromosomes (\(XX\)), while males have one X and one Y chromosome (\(XY\)). The allele for white eyes (\(w\)) is recessive. For a female to have white eyes (\(X^{w}X^{w}\)), she must inherit the recessive white - eye allele (\(X^{w}\)) from both her mother (\(X^{w}X^{-}\)) and her father (\(X^{w}Y\)). In nature, it is less likely for a female to receive two copies of the recessive allele compared to males (who only need one copy on their single X chromosome to show the white - eye phenotype, \(X^{w}Y\)).

Answer:

Females must inherit two copies of the recessive allele.