Consider the half reactions below for a chemical reaction. (pictured below) what is the overall equation for this chemical reaction? choices below

This is redox reaction. Redox is when one species reduces, that means gains electrons therefore known as a reduction reaction and the other species oxidises, gives out electrons and thats the oxidation reaction.
For reaction to be complete there should a oxidising species to give out the electrons and a reducing species to gain those electrons.
In the above reaction, Zn(s) gives out electrons therefore its oxidised to Zn2+ (aq) and Cu2+ (aq) gains electrons therefore its reduced to Cu (s).

2 electrons are being transferred so the 2 equations can be combined as it is, since the number of electrons are equal in both reactions.
When the 2 half equations are added, the 2 electrons are cancelled off leaving only the reactants. 
the correct answer is 1st response.

Technically speaking, histograms are another version of bar charts, if you need to work one out then skim through google hope-o that -o!

Try a or d, hope that