The rate of gas diffusion is ---Select--- proportional to temperature because a higher temperature means a/an increase in the kinetic energy of molecules. The rate of gas diffusion is ---Select--- proportional to the molecular weight of the gas because gas particles with higher masses require ---Select--- energy to move compared to gas particles with lower masses.

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.