(03.01 LC
Which of the following is not present in an atom? (1 point)

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

Which part of earth’s surface receives the most direct rays from the sun? a) equator b) ocean c) poles d) mountains

What is the independent variable in this investigation? mass volume sample number substance density