Why is it important that mitosis result in daughter cells that are exact copies of the original cell’s 46 chromosomes?

It is important because, 1) there is no diversity in mitosis for normal cells and 2) the cells can easily be used for repair and development.

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.