There are two species of sparrows that appear very similar to each other. a scientist tried tomate them. he observed that in spite of being of the same species, they didn’t interbreed. what evolutionary force must have worked in this example?
migration
geographical isolation
reproductive isolation

Reproductive isolation

Explanation:

The evolutionary force that must have worked to prevent interbreeding between the two species is reproductive isolation.

Reproductive isolation represents a series of mechanisms that either prevent fertilization between two organisms or ensures that the product of fertilization is rendered invalid or sterile.

If reproductive isolation acts to prevent fertilization, it is known as pre-zygotic and if it acts to render the product of fertilization sterile or invalid, it is referred to as post-zygotic reproductive isolation mechanism.

Migration is incorrect because migration does not lead to speciation. Rather, it has to do with immigration or emigration of organisms.

Geographical isolation is also incorrect because has to do with existence of geographical barrier or physical distance that enables the speciation of organisms.

"menstrual cycle is a complex cycle that consists of several processes. order of occurrence of steps in menstrual cycle are as follows:

1. high progesterone levels maintain the endometrium lining of the uterus.

2. endometrium lining breaks down and low levels of estrogen stimulate the pituitary to release fsh and lh.

3. fsh and lh stimulates the follicles to develop and the oocyte to produce estrogen.

4. rising estrogen levels suppress fsh production and development of other follicles.

5. a spike in lh causes follicle to rupture.

6. a breakdown of corpus luteum causes progesterone level to drop."

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