Final answer:
The root word 'phon' means 'sound,' and the term used to describe the loudness of sound is 'intensity level or decibel.'
Step-by-step explanation:
The root word “phon”, as found in words like telephone, phonics, and microphone, originates from the Greek word for sound. This root is indicative of the function of these objects or concepts related to the production, transmission, or reception of sound. Hence, the correct meaning of the root word “phon” is B. sound.
the word or phrase used to describe the loudness of sound is b. intensity level or decibel. The phon is a unit used to express loudness numerically and is related to the perception of loudness, whereas the decibel measures physical intensity.