Your answer is C forms of the same element that differ in the number of neutrons in each atom because if the number of neutrons change the whole element changes.
Based on the energy usage shown by the graph, the best option for the chemical change represented is the combustion of iron.
<h3>What chemical change is shown by the graph?</h3>
The combustion of iron in oxygen leads to the formation of Iron (III) oxide in solid form.
For the combustion of iron to happen, a lot of heat has to be applied to the iron which is why the potential energy of reactants is high. As the reaction progresses, the energy needed reduces as iron (III) oxide is formed.
Find out more on Iron (III) oxide at brainly.com/question/11885810.
