Which of the following best describes superconductors?

Question

1.conductors that have less than half the resistivity of iron
2.conductors with essentially no resistance below a critical temperature, peculiar to each material
3.conductors which have a drop in their resistivity as their temperatures are lowered
4.Conductors are materials which are very useful in a variety of ways; hence the name "superconductor."

Answer 1

2