For which of these questions could a testable hypothesis be developed? Check all that apply. A. Are gases better than solids? B. Do different liquids freeze at the same rate? C. Do cookies taste better when they are baked in a gas oven or in an electric oven? D. Does temperature affect the strength of a magnet? E. Does the color of water affect how quickly it evaporates?

Testable hypotheses could be developed for questions  B,  D,  and  E .

The main problem with  A  and  C  is the word "better".  This is a rubber word.  It means different things to different people, and it can mean different things to the same person at different times.  It's always a matter of opinion, it has no unique units of measure, and there is no concrete way to measure it.  Not good for developing a testable hypothesis.

heats surface water up

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia