You are an experienced naturalist and biologist and you observe two birds mating that you do not believe are members of the same species. The eggs from this breeding do not hatch, and when you obtain one of the eggs, you find embryonic development stopped not long after fertilization. Which of the following conclusions is supported by these observations? Please choose the correct answer from the following choices, and then select the submit answer button.
a. Behavioral isolation prevented successful production of offspring.
b. Temporal isolation prevented successful production of offspring.
c. Post-zygotic factors prevented successful production of offspring.
d. This evidence suggests the two types of birds are a single species.
e. Pre-zygotic isolation prevented successful production of offspring.