Question

what is a sensory receptor?
o a structure specialized to detect a stimulus
a structure which enhances the organs response to a stimulus
a bare nerve ending that senses heat or pain

Explanation:

A sensory receptor is defined as a structure specialized to detect a stimulus. The second option about enhancing the organ's response is incorrect as that's not the primary function. The third option is too narrow as sensory receptors are not just limited to bare nerve endings sensing heat or pain; they can detect various stimuli like light (in eyes - photoreceptors), sound (in ears - mechanoreceptors) etc.

Answer:

a structure specialized to detect a stimulus