Which describes the oxidizing agent in a chemical reaction?
a. the substance that is oxidized because it loses electrons
b. the substance that is reduced because it loses electrons
c. the substance that is oxidized because it gains electrons
d. the substance that is reduced because it gains electrons

Hello
The term "oxidizing agent" itself is very helpful in this question. An "agent" of something is an entity that carries out the required task. Thus, an oxidizing agent must oxidize. In order for it to oxidize something else, it must itself be reduced. Now we discuss the movement of electrons.
Defining oxidation as the increase in oxidation state, eg from +1 to +2, we see that charge is becoming more positive. Thus, to increase positive charge, electrons must be removed. The opposite is true of reduction.
Something that is helpful in remembering this is OIL RIG
Oxidation is loss (of electrons) Reduction Is Gain (of electrons)
Therefore, the answer is D

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.