Thermal energy by way of an internal combustion engine yields ______ energy.

 An unproved assumption used to explain certain facts is

 The superposition of waves, producing regions of reinforcement or regions of cancellation is called

 In the equation  represents

“You can’t break even” refers to the

 Sunspots appear dark because they are:

 Another name for the manipulated variable is

The energy of a main sequence star comes from:

An elongated celestial object containing a coma, nucleus, tail, and a hydrogen cloud is a (an):

The frequency of an electromagnetic wave is a function of