Question

which receptor detects heat and stretch?
free nerve endings
merkel disk
ruffini corpuscle
meissners corpuscle

Explanation:

Free nerve endings are unencapsulated sensory receptors that detect thermal stimuli (including heat) and mechanical stimuli such as stretch. Merkel disks detect light touch and pressure; Ruffini corpuscles detect stretch but not heat; Meissner's corpuscles detect light touch and vibration.

Answer:

A. Free nerve endings