Fact 1: Some touch receptors sense differences in temperature or pain.

Fact 2: Merkel's discs are touch receptors.

Given the two facts above, answer the question "What sense differences in temperature or pain?" with the following options: 
- Veins and arteries.
 - the skin
 - Merkel's discs
 - movie discs
 - frontal zones
 - cd discs
 - sensory neurons
 - sound discs


 

   Merkel's discs      