Calculate the atomic mass of the element

Ineed ! it’s science and it’s due tomorrow!

Zoe is investigating the composition of substance a, an unknown substance. using chemical processes, she analyzes substance a and determines it is composed of sodium, oxygen, and hydrogen atoms in a ratio of 1 : 1 : 1. what is substance a? a. a compound b. an element c. a heterogeneous mixture d. a homogeneous mixture

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