Since the Pleistocene ice age, deserts have been gradually forming in the southwestern United States. As the original lakes and rivers of this area shrank into isolated streams, ponds, and springs, the fishes living in them developed a strong potential for .(A) speciation.(B) hybridization.(C) mechanical incompatibility.(D) temporal isolation.(E) hybrid inviability.

(A) speciation.

Explanation:

Shrinking of water bodies and development of deserts since the Pleistocene ice age produced new vacant niches that could be inhabited by organisms such as fishes. Production of new isolated streams, ponds, and springs allowed the fishes to occupy these new water bodies. Accumulation of genetic variations to become adapted to their new habitat resulted in the evolution of several new species of fishes with many different genetic traits. This represents speciation due to geographical isolation.

"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."

if your own plato the answer is b. the fern transitioned from sporophyte generation to gametophyte generation.