Answer:
a) Natural selection may lead to the evolution of prezygotic reproductive isolation in organisms that already have postzygotic isolation to prevent wasted reproductive effort
Explanation:
Prezygotic reproductive isolation produces postzygotic reproductive isolation because this mechanism lead to genetic differences that impair the pairing of homologous chromosomes during meiosis.
Exposure to environmental tobacco smoke causes approximately 45 to 46,000 non smokers to die of heat diseases annually. Smoking harms the cardiovascular system in many ways which include; damaging the lining of arteries, reduces HDL, good choresterol, Raises LML, bad cholesterol, increases blood pressure and heart rate, it also causes the platelets to stick together in the blood stream and speeds the development of fatty deposits in the arteries among other risk factors.
In adults, stem cells remain undifferentiated until they are needed to repair or replace other cells. Stem cells can produce cells that are identical to themselves.
When guard cells lose potassium ions, water diffuses out of the cells by osmosis. As water leaves the cells, they become flaccid and less bowed, which closes the stomata between them.
Answer:
Essential amino acids cannot be made by the body. As a result, they must come from food. The 9 essential amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
Explanation:hope it helps
