Trueeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
The central nervous system of the frog is different from that of humans; if the optic nerve of a frog is cut, the animal will be able to see again within weeks but the same damage in humans would cause permanent blindness :).
Answer: More than 99 percent of all organisms that have ever lived on Earth are extinct. As new species evolve to fit ever changing ecological niches, older species fade away. But the rate of extinction is far from constant. At least a handful of times in the last 500 million years, 75 to more than 90 percent of all species on Earth have disappeared in a geological blink of an eye in catastrophes we call mass extinctions.
Though mass extinctions are deadly events, they open up the planet for new forms of life to emerge. The most studied mass extinction, which marked the boundary between the Cretaceous and Paleogene periods about 66 million years ago, killed off the nonavian dinosaurs and made room for mammals and birds to rapidly diversify
Answer:
B. Proteins
Explanation:
Salivary amylase is an enzyme that starts the breakdown of starch in the mouth. Gastric glands of the stomach secrete gastric juice, which contains HCl to kill bacteria and denatures proteins, intrinsic factors, and the enzyme pepsin. The chief cells of gastric glands secrete pepsinogen (an inactive form of pepsin).
Pepsin begins the digestion of proteins in the stomach. It breaks down certain peptide bonds between amino acids and thereby, breaks down protein chain into smaller peptide fragments. Pepsin requires a very acidic environment of the stomach (pH 2) and becomes inactive at a higher pH.
