Ben observes how quickly some dry wood is burning in a campfire. which term best relates to ben's observation?

I think this the the list of choices relating to the above question.
reaction rate 
activation energy 
collision theory 
spontaneous reaction

The term that best relate to ben's observation is REACTION RATE.

Reaction rate is defined as the speed at which the chemical reaction proceeds. It either is the amount of concentration of a product in a given unit of time or the concentration of the reactant that is being consumed in a unit of time.

Reducing agents  oxidized by the reaction 

Remember that rust prevented by placing a sacrificial electrode in electrical contact with the iron. the sacrificial electrode must be composed of a metal that  oxidizes  more easily than iron (that is, it must be below iron in table 18.1).