The earth's crust is: made of rock
the thinnest layer
broken into large pieces called plates
all of the above

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

Chlorophyll a had the molecular formula c55h72mgn4o5 how many atoms are in this molecule

State the effect on the concentration of the clo- ion when there is a decrease in the concentration of the oh- ion