Answer:
Postzygotic barrier
Explanation:
The reason why the species died due to genetic difference or genetic variation after the species produced zygote and begins to develop was because of what is called POSTZYGOTIC BARRIER.
POSTZYGOTIC BARRIER is a barrier or otherwise obstacles that does not allow offspring that are fertile and capable of producing a specie to form by preventing the formation after the species has begin to develop which is the development stage thereby making the already formed species to die.
