Why does the number of chromosomes in a cell double prior to the beginning of mitosis?

Mr. olajuwan was in a horrific snowmobile accident. afterwards he had trouble walking and he had a loss of balance. which of the 4 major brain region was probably demaged

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 organisms listed below performs nitrogen fixation? a. legumes b. plants c. bacteria d. fungi