Answer:
He discovered neutrons in 1932
My best try would be d an element
The answer is B
If one circuit fails, it is most likely that all the components in the circuit will fail.
H2O+Fe⇒Fe2O3+H2
When it is balanced it would be:
3H2O+2Fe⇒Fe2O3+3H2
When balancing equations, you have to make sure that all elements are equal on each side.