Biochemical recognition systems within the stigma of a flowering plant prevent the pollen from a different species from developing a pollen tube and fertilizing its eggs. This is an example of what kind of reproductive isolation?

A. post-zygotic, temporal separation
Bpre-zygotic, lock and key
C. pre-zygotic, behavioral isolation
D. post-zygotic, ecological separation
E. pre-zygotic, temporal separation

The correct answer is - option B. pre-zygotic, lock and key.

Explanation:

Reproductive isolation is the method or process that involves preventing the particular species from mating and producing offspring in nature. Prezygotic isolation keeps the fertilization to occur that is the reason it termed as the pre-zygotic isolation or barrier.

Lock and key isolation system is a hypothesis that suggests that reproduction isolation can be increased due to the species-specific morphological compatibility of male and female reproductive parts like presented in the question.

Thus, the correct answer is - option B.

nucleus

would be most reasonable answer tbh