Can someone plz me in this for number 1. only

Which sentence about particles in matter is true? a. atoms are present in solids and liquids but not in gases. b. the particles of matter are in constant motion. c. the same kinds of atoms are found in different elements. d. when a solid changes to a liquid, the sizes of the particles change.

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation:

Ais a mountain created from eruptions of lava, ash, rocks, and hot gases.