At higher concentrations, particles of reactants are crowded closer together, so they are more likely to collide and react.  If Mona has filled a balloon with helium and she removes some gas from it, what happens to the likelihood that the helium particles will collide with each other more likely or less likely?
less likely

The voice becomes deeper as the larynx in the throat grows larger.  If your larynx were to grow, your voice would become more or less deep?
more

Differences in air pressure over the surface of the Earth result in wind. The greater the differences in air pressures, the stronger the wind.  When you have air pressures change very little what happens to the wind decreases or increases?
decreases

If there are more greenhouse gases in the atmosphere, more ultraviolet radiation will be trapped and the Earth will heat up.  Tony drives an SUV that contributes many greenhouse gases to the atmosphere. Evan rides a scooter that contributes few greenhouses gases to the atmosphere. Who likely contributes more to the Earth heating up Tony or Evan?
Tony