Which type of organic reaction is characterized by the recombination of radicals, as depicted in the experimental results shown in the figure?

Focus on radical recombination: Radical recombination is a termination step where two radicals combine to form a stable, non-radical product. This is characterized by the disappearance of radical species.

Differentiate from other reaction types: Radical substitution involves radicals replacing atoms in a molecule, electrophilic addition involves an electrophile adding to a double bond, and nucleophilic substitution involves a nucleophile replacing a group in a molecule. None of these involve the recombination of radicals.