Answer:
The nucleus of an atom consists of Protons and Neutrons.-A.
Answer: Avogrado's Constant
Explanation:
One mole of a substance is equal to 6.022 × 10²³ units of that substance (such as atoms, molecules, or ions). The number 6.022 × 10²³ is known as Avogadro's number or Avogadro's constant. The concept of the mole can be used to convert between mass and number of particles.
The correct definition of density is the degree of compactness of a substance.