Question

hemophilia is a sex - linked recessive disorder. which of the following individuals does not have hemophilia (h), but is a carrier for the disease?
options: xhxh, xhxh, xhxh, xhy, xhy
question 8
1 pts
dwarfism is a recessive disease found on the 4th autosome. if rebecca has dwarfism, what should her genotype be?
options: dd, dd, xhxh, xhxh, xhxh
question 9
1 pts
a long middle toe is a dominant trait found on the 20th autosome. carrie has a long middle toe. what is one possible genotype for her?
options: tt, tt, xtxt, xtxt, xhy

Explanation:

Question 7 (Hemophilia)

Hemophilia is X - linked recessive. A carrier has one normal (H) and one mutant (h) allele on X - chromosomes. For a female carrier (since males can't be carriers for X - linked recessive as they have one X), the genotype is $X^H X^h$. Males have $X$ and $Y$; if they don't have hemophilia, their X is $X^H$, so genotype $X^H Y$. But the question asks for a carrier (so female with $X^H X^h$? Wait, no: the question says "does not have hemophilia (h), but is a carrier". Wait, hemophilia allele is h, so normal is H. A carrier for X - linked recessive (female) has $X^H X^h$ (has one h, so carrier, but doesn't show the disease as H is dominant). Wait, the options: let's check the options. The options are XHXH, XHXh, XhXh, XHY, XhY. A carrier must have one h. XHXH: no h, not carrier. XHXh: has one h (carrier), doesn't have hemophilia (since H is dominant). XhXh: has hemophilia (recessive homozygous). XHY: male, no h, not carrier. XhY: male, has hemophilia. So the carrier (doesn't have hemophilia but carries h) is XHXh. Wait, but the options: let's re - read. The question: "Hemophilia is a sex - linked recessive disorder. Which of the following individuals does not have hemophilia (h), but is a carrier for the disease?" So the correct genotype is $X^H X^h$ (or XHXh in the options).

Dwarfism is autosomal recessive. So the genotype for having the disease (recessive) is homozygous recessive (dd). Because in autosomal recessive, the disease is expressed when both alleles are recessive (dd). DD is homozygous dominant (no disease), Dd is heterozygous (carrier, no disease), dd is homozygous recessive (has disease). So if Rebecca has dwarfism, her genotype is dd.

Long middle toe is dominant (T). So possible genotypes for a person with the dominant trait are homozygous dominant (TT) or heterozygous (Tt). The options are TT, tt, XTXT, XXt, XHY. Wait, maybe typo, but assuming the trait is autosomal dominant (since it's on 20th autosome), so dominant allele is T. So possible genotypes: TT (homozygous dominant) or Tt (heterozygous). From the options, TT or Tt? The options have TT, tt, XTXT, XXt, XHY. Wait, maybe the alleles are T (dominant) and t (recessive). So Carrie has long middle toe (dominant trait), so possible genotypes are TT or Tt. Among the options, TT is a possible genotype (homozygous dominant).

Answer:

XHXh (assuming the option with XHXh is one of the choices; from the visible options, the correct one is the one with XHXh, e.g., if the options are as shown, the correct option is the one labeled with XHXh)

Question 8 (Dwarfism)