There is no answer that is right except for C. Natural Selection.
Genetic Recombination doesn't change gene frequency;nor does migration. (Unless it's local)
Mutation could be the answer, but since mutations are too rare to really power Evolution, the only logical answer is Natural Selection.
Answer:
Digestion is the process of converting complex food any individual eats, into the smaller components and nutrition that is absorbed and assimilated into the body to produce energy and nutrition for the cell and body. The digestion process takes place in the digestive system that includes the gastrointestinal tract and organs like the liver and pancreas.
It includes ingestion of food through the mouth or buccal cavity, propulsion of food, physical digestion by making it small pulp with help of peristalsis, chemical digestion by the enzymes and acid, absorption through the intestine into the blood, and defecation of waste.
Explanation:
amphibians have smooth, sticky wet and highly porous skin to perform various functions.
reptiles have a dry, hard and scaly skin, which guards them in harsh conditions.
amphibians lay their eggs in water and cover them with gel.
reptiles lay their eggs on land and have a hard protective shell.
