(1) All living things are made up of cells, (2) Cells are the smallest units (or most basic building blocks) of life, and (3) All cells come from preexisting cells through the process of cell division. Anybody know this?

Which demographic challenge is europe currently experiencing? a. an aging and decreasing population b. a baby boomc. an unequal distribution between males and females d. a large group of teenagers moving through the school system(i chose a but i'm unsure)