Which cell component functions like the digestive system in the human body?

Explain how sequences of amino acids in proteins can be used to reveal relationships among organisms.

An ecologist studied the same species of deer during the summer and the winter. she noticed that during the summer, when there was plenty of food, the deer were energetic and playful. however, during winter when food was scarce, the deer moved more slowly and did not run unless they needed to escape a predator. which scientific fact is best supported by her observations?

Which is a function performed by stem cells in the skin a. replacing lost skin cells b. making cells for the intestines c. growing new organs d. differentiating into brain cells plz apex