Why is the cell membrane described as being selectively permeable?
a. it allows anything to enter and exit the cell.
b. it allows nothing to enter or exit the cell.
c. it allows only water to enter the cell.
d. it allows needed materials to enter the cell and wastes to leave the cell.

Connection compare and contrast genetic engineering to the process of natural selection. select all statements that are true.

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.

Linda and julia are trying to determine whether their ideas are scientific or pseudoscientific. linda's idea is free of bias. julia's idea gives the same result when tested repeatedly. which statement is correct about linda and julia's idea?