What is dark energy ? a) the energy associated with the matter that has fallen into a black hole b) the matter-energy needed to bridge the gap between the energy we see or infer and the energy needed to make the universe flat c) the energy associated with dark matter d) the unseen matter-energy needed to make the observed curvature of space spherical (as we believe it should be), while the observed matter-energy only makes it hyperbolic

For the given question, out of the four options provided,

Option B) is correct.

Explanation:

Dark energy is a hypothetical form of negative energy and exerts a pressure which is repulsive in nature which acts against gravity and is said to be responsible for the expansion of the Universe.

It is thought that the emergence of universe from a singularity is follwed by rapid expansion within a very less time with inflation that began just after after the 'Big Bang' in order to smoothen the Universe and to make the Universe geometrically flat.

You are correct, the answer is C. 

Good insulators are materials that do not allow heat, electricity, light or sound pass through easily. Materials like steel and silver (which are metals) are not good insulators because they make good conductors. They easily allow heat, electricity and the like pass through them. 

Thus, the answer is letter C. Rubber.