Explain why cells are the basic units of structure and function in organisms

They are the basic units of structure because they are the smallest unit of life. you cant go any further. also they make up every living thing from prokaryote to eukaryote.

Cells are what make up everything which is why they are basic units, nut inside this basic unit is a whole functioning organism with parts in it that help make everything work. think of a cell like a clock. different gears move different things and if one was missing the clock wouldn't work. they all work together to make the clock (cell) run and do it's job, whatever that may be. idk if this answered your question but I hope it helps you understand better.

C) to ensure each new cell has an exact copy of the dna