Answer:
Complex organic food molecules such as sugars, fats, and proteins are rich sources of energy for cells because much of the energy used to form these molecules is literally stored within the chemical bonds that hold them together.
Explanation:
Answer: The cell is the structural and functional unit of all living organisms, and is sometimes called <u>the "building block of life."</u> Some organisms, such as bacteria, are unicellular, consisting of a single cell.
Sleep is an example.
Circadian rythms are biological processes that repeats itself within a certain time frame, as sleep repeats itself approximately once every day.
reproduction, heredity, variation in fitness or organisms, variation in individual characters among members of the population.