Nico uses wire to connect a battery, a lightbulb, and a switch, but the bulb does not light up. which might explain this problem? a. the battery has too much power. b. the wires are bent. c. the circuit is closed. d. the switch is open.

(D) The switch is open , which implies that no current flows in the circuit.  (ANS)

Bent wires are of no problem unless the wires get cut which is not the case.

The circuit is closed, will actually help the bulb light up.

Much power depends on the bulb power rating which I am sure the examiner did not put in mind ( actually higher power = more light ) however, after the power given exceeds the power rating the bulb will burn out. 

The center is basically the heart of it

Amicroscope, because these cells are so small that you would not be able to see them, or what they attack without it.