Superconductors are those elements A. Whose conductivity is intermediate between metals and insulators B. Whose resistance falls almost to zero at very low temperatures C. Which turn into insulators at very low temperatures D. Which conduct electricity only at super-high temperatures

The correct answer is: B. Whose resistance falls almost to zero at very low temperatures.

Superconductors are materials that conduct electricity with no resistance. This means that a current can flow through a superconductor without any loss of energy. Superconductors are made of materials that have a special property called superconductivity. Superconductivity is only possible at very low temperatures.

Option A is incorrect because superconductors have a very high conductivity, not an intermediate conductivity.

Option C is incorrect because superconductors

Option D is incorrect because superconductors conduct electricity at very low temperatures, not at super-high temperatures.