In a chemical change, the substance that you end up with is the
a. reactant
b. product
c. displacement element
d. exchange element

The reactant is what you begin with.
The product is what you end up with (so the answer is B)

Atomicity occurs to prevent updates of the database occurring only partially, which can cause greater problems than rejecting the whole series outright.some are monatomic, diatomic, triatomic etc because it shows the number of atoms. for example, monatomic means it contains only one atom.