The diameters of the spheres are 72.5 meters square
C. You should ALWAYS ask the teacher if you don't get something; your friends could be wrong, don't guess it, and NEVER cheat. Hope this helps!!
The question asks average kinetic energy. So it is only related with the temperature. The higher temperature is, the higher kinetic energy is. So the answer is (4).
I believe it is C, as helium is one of the lightest noble gases making the particles move faster.
