since the number of atoms in a substance is so large, a unit to count them was created. This unit is the number of atoms in 12 grams of carbon-12 is known as

The mole was previously defined as the number of atoms determined experimentally to be found in 12 grams of carbon-12. The number of units in a mole also bears the name Avogadro's number, or Avogadro's constant, in honour of the Italian physicist Amedeo Avogadro.

Explanation:

I'm not entirely sure if i'm right but I hope this helps.

that's what i got you can count the number of atoms

the right answer is c i just did the question.