A daughter has hemophilia, a recessive sex-linked trait. Which are possible genotypes of her parents?
A. XHxh and Xhy
B. XHXH and xhy
c. xhxh and XHY
D. XHxh and XHY

D. XHxh and XHY

Explanation:

since this is the only answer with genes that share a common allele, the answer is D.

In order for a recessive gene to be present, the daughter must have gained the alleles of XHXH, which in this case, is a 25% chance. The other two possibilites are XHxh, XHY, and Yxh. To further prove this, a female must have 2 X alleles and to have hemophilia, they must carry 2 H's. If they were to only have one H, they would be a carrier instead of a product.

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands