Question

based on the pedigree that is shown, which describes john?
carrier for hemophilia
expresses hemophilia
does not have hemophilia
expresses hemophilia and died of complications

Explanation:

Step1: Identify hemophilia inheritance

Hemophilia is X-linked recessive: males ($X^hY$) express it; females need $X^hX^h$ to express, $X^HX^h$ are carriers.

Step2: Analyze John's parents

Father: $X^HY$ (gives $X^H$ to daughters, $Y$ to sons). Mother: $X^HX^h$ (can give $X^H$ or $X^h$).

Step3: Determine John's genotype

John is male, gets $Y$ from father, $X^h$ from mother. Genotype: $X^hY$.

Step4: Match to phenotype

$X^hY$ genotype means he expresses hemophilia.

Answer:

expresses hemophilia