Which combining form indicates a meaning associated with "light"?

The combining form "phot/o" is derived from the Greek word for light, specifically relating to light in various contexts within medical terminology. It is widely used in terms such as "phototherapy," indicating treatments involving light, and "photophobia," which describes a sensitivity to light. Understanding this root is essential in medical terminology, as it allows for better comprehension of terms that involve light exposure or conditions affected by light. The other choices do not relate to light; "phob/o" pertains to fear, "phalanges" refers to the bones of the fingers and toes, and "pharyng/o" relates to the pharynx. Thus, "phot/o" is the correct choice for indicating a meaning associated with light.