|Distance traveled divided by elapsed time is average ____.
|Solar energy is converted into chemical energy by ____.
|The ability to do work or to cause change is ____.
|There are about 2.5 centimeters (cm) in one ____.
|Radio waves have a lower ____ than x-rays.
|Radio waves have a longer ____ than x-rays.
|Weight is measured with a ____.
|The mass of a $1 bill is about one ____.