|Heating a helium-containing balloon will cause it to ____.
|At the top of a mountain, water boils at a ____ temperature.
|Unlike gravity, friction is a ____ force.
|Water freezes at 32° and boils at 212° ____.
|If you move at a ____ velocity, your acceleration is zero.
|Mass and distance determine ____ force.
|Water ____ and becomes less dense when it freezes.
|Some light can pass through a ____ substance.