Which criteria are responsible for deciding whether a heterogeneous mixture is a colloid or a suspension? 
whether its composition is uniform and transparent whether the particles remain suspended for an extended period of time
whether it can be separated into simpler substances through physical separation techniques
whether the ratio of components is fixed

How does a sample of helium at 15 degree celsius compare to a sample of helium at 215 k? a) the helium at 15 degrees celsius has a higher average kinetic energy that the sample at 215 k. b) the helium at 15 degrees celsius has lower nuclear energy that the sample at 215 k. c) the helium at 15 degrees celsius has slower- moving atoms that the sample at 215 k. d) the helium at 15 degrees celsius has smaller atoms than the sample at 215 k.