If two individuals from different species attempt to mate, but fertilization fails to occur, this is likely the result of. However, if such a mating produces a zygote that fails to form a viable embryo, this is likely the result of.
a. pre-zygotic factors; post-zygotic factors.
b. post-zygotic factors; pre-zygotic factors.
c. behavioral factors; pre-zygotic factors.
d. pre-zygotic factors; behavioral factors.
e. post-zygotic factors; lock-and-key factors.

Explanation:

Fertilization is the process of fusion of  male gamete (sperm) and female gamete (egg). Before fertilization, all the events are known as pre-fertilization events and those which occurs after fertilization are known as post-fertilization events.

There are various factors which help in fertilization. All species contain some receptors on the membrane of egg which play very important role in fertilization and prevent fertilization between inter-species.

The mating in which the formation of zygote is occurs but it is unable to form a viable embryo,  is due to the result of post-zygotic factors.

the answer is c on e2020, bud.