A common birth defect characterized by an opening between the upper lip and the nose is called Cleft Lip. Cleft lip happens during the early stage of pregnancy. This occurs when there is an unsuccessful connection in the face and lip area while the fetus is developing inside the womb. Both cleft lip and cleft palate are successfully treated with surgery.
Semen is the correct answer
The correct answer is A. maintaining homeostasis.
Homeostasis is a term referring to an organisms continuous process of maintaining and auto-regulating the conditions of its internal environment. Variables such as pH, temperature, and fluid balance need to be at optimal conditions in order for the organism to function properly.
In this example, the phosphate buffer system permits the organisms to maintain a constant pH in their intracellular fluid. This is one of the organism's homeostatic mechanisms.