HELP PLEASE, its a test due now

Students in biology are studying the macromolecules of life. they used a calorimeter to determine the calories in various types of food. once the lab was completed, the students ate the left over food samples. monica commented that in just 6 or 7 "chews" of the saltine, it was gone; nothing but a sticky paste in her mouth. elaborate on what happened chemically while chewing the saltine. include the macromolecules present.

Which of the following is an eon in the time scale? phanerozoic proterozoic archean all of the above

Which of the following explains why a tree is often used as a model to represent the principle of common descent