Please answer asap its important

The combining of light nuclei is called blank. blank as in not actually blank. you know what im tryin to say.

Select the best definition for wavelength. the height of an oscillating electromagnetic wave the rate at which electromagnetic waves oscillate. the distance between two crests of an electromagnetic wave. the oscillations of electric and magnetic fields select the best definition for frequency. the oscillations of electric and magnetic fields. the height of an oscillating electromagnetic wave. the distance between two crests of an electromagnetic wave. the rate at which electromagnetic waves oscillate

Which of the following best explains what happens when the kinetic energy of particles in a liquid state decreases?