The principle which allowed Marta to find her dog Roxy is known as an: d. absolute threshold.
An absolute threshold can be defined as the smallest (lowest) level of stimulus such as light, touch, sound, etc., that can be detected by a living organism, usually half the time.
In this scenario, a principle which allowed Marta to find her dog Roxy amid all of the other barking dogs is known as an absolute threshold.
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