Once you have been exposed to an antigen, you develop immunity against the same antigen because

The image shows embryos of three vertebrate classes

In the diagram below, the northern hemisphere would be in what season at position a a.fall b. winter c.summer d.spring

Duchenne muscular dystrophy is a serious condition caused by a recessive allele of a gene on the human x chromosome. the patients have muscles that weaken over time because they have absent or decreased dystrophin, a muscle protein. they rarely live past their twenties. how likely is it for a woman to have this condition? a) women can never have this condition.b) one-fourth of the daughters of an affected man would have this condition.c) one-half of the daughters of an affected father and a carrier mother could have this condition.d) only if a woman is xxx could she have this condition.