Here's why:

* Atoms are the fundamental building blocks of all matter. They are incredibly tiny, measuring in nanometers (one billionth of a meter).

* Cell organelles are structures within cells that perform specific functions. They are made up of many molecules, which in turn are made up of atoms. Organelles are much larger than atoms, typically measuring in micrometers (one millionth of a meter).

Think of it like this:

* Atom: A single brick

* Cell Organelle: A house built from many bricks

So, a cell organelle is like a house built from many, many atoms!