2. Imagine a new planet was discovered. Astronauts will be visiting soon. Prior to landing on the planet, located between Earth and Mars, the scientists working on the voyage and the discovery first write a hypothesis:

During cooling, the kinetic energy of the molecules falls. why does this happen? a.the motion of the molecules increases. b. the motion of the molecules slows down. c.the van der waals forces between molecules decrease d. the forces of attraction between the molecules are overcome.