Which change represents an oxidation reaction?

An oxidation-reduction (redox) reaction is a type of chemical reaction that involves a transfer of electrons between two species.  

Fe+Cu  

2+

⇌Fe  

2+

+Cu

In the above reaction, Fe is oxidised by gaining 2 electrons while Cu is reduced by loosing 2 electrons.

Hence the above reaction is represents an oxidation-reduction reaction.

Hence the required answer is (E)Fe+Cu  

2+  ⇌Fe  

2+  +Cu.

1.43 x 10^-11 j the guy commented the awnser just making sure u see it .

geosphere and hydrosphere.

this is because the geosphere has to do with geological events, while the hydrosphere controls all water on earth.