What do the carbon, oxygen, and nitrogen cycles all have in common? a. they all include an exchange of gases with the atmosphere. b. none of the cycles are biogeochemical cycles. c. they are all byproducts of photosynthesis. d. they all sustain life, but living organisms have no part in the cycle.

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.