Brown hair color as (R, dominant) and blonde hair color was (r, recessive).

1)If hair color was an autosomal Mendelian trait, and an XX parent was heterozygous while an XY parent was homozygous dominant, what percentage of their offspring would have brown hair?

2) if hair color was an X-linked trait, and an XX parent was a carrier while an XY parent had brown hair color, what percentage would have brown hair?

3) Can an XY parent be a carrier for blonde hair? Why or why not?