Some single-celled organisms that make copies of themselves through mitosis. which decribes the function of the cell cycle in such single-celled organisms?

The correct answer would be a reproduction.

Mitosis is a type of cell division in which a single cell is divided to produce two identical daughter cells.

In multi-cellular organisms, mitosis plays an important role in growth and repairs of cells.

However, in single-celled organisms, it is used as a mode of asexual reproduction in which a parent cell divides into two identical daughter cells.

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.