House cats and domestic dogs live in the same environment, often in close relationship with one another. However, they cannot interbreed. Why not?
A) They don't look alike.
B) They are not in the same species.
C) They do not get along well enough.
D) They do not have the same reproductive cycle.

              B) They are not in the same species.

Explanation:

                     Cat and dog both are domestic animals but the can not interbreed to produce fertile offspring. Specie is define as those animal which can interbreed to produce fertile offspring so the cat and dog can not interbreed as they belong to two different species. Both species have different chromosome number that's why the can not interbreed. In order to interbreed both the organisms must belong to one specie. E.g As both tiger and lion live in one environment and the interbreed and produce tiglion but it is infertile and can not breed to produce offspring.

the cell cycle is the final answer! : )