Oxidation-reduction reactions

A. must include a transfer of electrons from one atom or ion to another.
B. must include oxygen.
C. do not need to have both an oxidation and a reduction reaction.
D. can include an atom or ion being reduced without an atom or ion being oxidized.

Question

Oxidation-reduction reactions 
    
A. must include a transfer of electrons from one atom or ion to another.
B. must include oxygen.
C. do not need to have both an oxidation and a reduction reaction.
D. can include an atom or ion being reduced without an atom or ion being oxidized.

anonymous · Answer

@nechirwan could you help?

nechirwan · Answer

An oxidation-reduction (redox) reaction is a type of chemical reaction that involves a transfer of electrons between two species. An oxidation-reduction reaction is any chemical reaction in which the oxidation number of a molecule, atom, or ion changes by gaining or losing an electron.

anonymous · Answer

http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch19/oxred_1.php