Question

ensure safety in the laboratory
in a conductivity apparatus, like the one above, you should never touch the while the power is on.
done
lightbulb
leads
wires
base of battery
done

Explanation:

In a conductivity lab setup, when power is active, the leads are submerged in the conductive solution and carry an electrical current. Touching them poses a direct electric shock hazard, unlike the insulated wires, enclosed battery base, or the lightbulb which is not a direct current-carrying contact point in this context.

Answer:

leads