Which layer best represents the mantle?
A. 1

B. 2

C.3

D.4

when a reversible reaction is occurring in both directions at the same rate; the products and reactants do not change in concentration. a chemical reaction where the compound is broken into its constituent parts.

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explanation: bc blah

all matter is made up of atoms

in any element all atoms are the same

elements in a compound are always in a constant ratio: apex

the atmospheric gas that forms a mild acid when dissolved in water is called carbon dioxide. the correct answer is a. 2.) chemical weathering would cause an inscription on a marble headstone to become harder and harder to read over time.