Parietal cells within the stomach lining secrete hydrochloric acid that lowers the pH of the stomach. A low pH (1.5 to 2) activates pepsin. Acetylcholine, gastrin, and histamine stimulate the proton pump in parietal cells to release hydrogen ions and decrease pH.
Answer:<em> Living organisms must maintain a constant internal environment while living in a constantly changing external environment. </em>
Explanation: Maintaining the internal environment is important because the processes that keep the cell alive can only take place under certain conditions. There are different processes that occur in the body to maintain the constant internal environment such as diffusion, osmosis, homeostasis, active transport, passive transport, endocytosis, exocytosis, etc. Homeostasis helps to maintain an equilibrium of an internal environment.
Chicken with feather or depending on what you cross breed it with
There are two groups of bases: Pyrimidines: Cytosine and Thymine each have a single six-member ring.
