If a keystone species is removed from an ecosystem,
a. only abiotic factors can be affected.
b. only biotic factors can be affected.
c. neither abiotic nor biotic factors can be affected.
d. abiotic and biotic factors can be affected.

D. abiotic and biotic factors can be affected.

each of the 46 original chromosomes splits into two daughter chromosomes, so there are two sets of 46 daughter chromosomes that end up in each cell. human cells have 46 chromosomes. each chromosome consists of a pair of identical chromatids attached together by a structure called a centromere.