10. Speciation occurs when: a. two populations become geographically isolated
b. enough differences accumulate between two populations that they can no longer interbreed
C. gene mutations accumulate
d. all of the above

explanation:

the universal gravitation equation. since the gravitational force is directly proportional to the mass of both interacting objects, more massive objects will attract each other with a greater gravitational force. if the mass of one of the objects is doubled, then the force of gravity between them is doubled.

a. to encourage apoptosis

multiple allele inheritance is traits controlled by more than 2 alleles (ex: pigeons having 3 alleles of one gene govern their feather color).   so the answer is a.