Which statement is true regarding the transmission of sex-linked traits in a population? O Males cannot carry recessive alleles for sex-linked traits.
O Males cannot express dominant alleles on the X chromosome.
O Males cannot express recessive alleles on the X chromosome.
O Males cannot pass alleles for sex-linked traits to their daughters.

none of the statements are true

Explanation: Males can have a recessive copy of a X-linked gene, and can pass that on in the X containing gamete and so pass it on to daughters,  but not to male offspring. Males will express whichever allele, dominant or recessive that they carry.

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.