Here's why:

* Plasma is a state of matter where atoms are stripped of some or all of their electrons, resulting in a mix of ions and free electrons. It's often described as the "fourth state of matter."

* Gas is a state of matter where atoms or molecules are relatively far apart and move freely.

During recombination, the free electrons in the plasma recombine with the ions, forming neutral atoms or molecules. This process releases energy, usually in the form of light or heat.

Think of it like reversing the process of ionization:

* Ionization: Gas --> Plasma (electrons get stripped away)

* Recombination: Plasma --> Gas (electrons recombine with ions)