Question

what is one example of the use of an infrared sensor?
bar code scanner tracks store inventory
monitoring feed for farm animals to keep them healthy
detecting the presence of humans trapped under collapsed buildings
information is relayed to a visually impaired individual about the location of objects

Explanation:

Infrared sensors detect heat emitted by objects. Humans emit body heat, so these sensors can locate trapped people under collapsed structures by picking up their infrared radiation. Bar code scanners use lasers, not infrared. Monitoring animal feed and aiding visually impaired individuals with object location do not rely on infrared sensor functionality.

Answer:

detecting the presence of humans trapped under collapsed buildings