One scientific hypothesis about the origin of life holds that

A.

RNA replaced DNA as the most stable information-storing molecule.

B.

RNA existed before DNA.

C.

proteins that duplicate themselves came to function in information storage.

D.

as cells evolved they stopped using RNA entirely.

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.

Northern switzerland has a fairly cold climate caused by sea winds from the atlantic ocean but souther switzerland tends to be much warmer and sunnier, what could cause this difference?

An alaskan spruce forest will burn easily once burned the forest regenerates fairly wuickly which statement best describes haw an alaskan spruce forest reacts to fire? it is resilient