Oxygen molecules are sixteen times as massive as hydrogen molecules. At the same temperature, which type of molecule would you expect to move faster?

hydrogen molecules.

Explanation: in same temperature molecules have same average kinetic energy.

You can estimate it solving E = 3/2 kT = 1/2 mv². Constant k is Boltzmann constant.

Lighter molecule has greater speed

it cools slower in the earth meaning the crystals have more time to form than lava on the surface

the darker peppered moth species were favored due to the fact that the industrial revolution had made all the nearby trees a darker color instead of white.