Question

radiation is
the number of crests of a wave in a
the distance from one crest of a wave
given amount of time
to the next
the transfer of energy by
a distrubrance that transmits energy
electromagnetic waves

Explanation:

Radiation is the transfer of energy by electromagnetic waves. The first option describes frequency, the second describes wavelength, and the fourth describes a wave in general.

Answer:

The transfer of energy by electromagnetic waves.