All vertebrates have general sensors in their skin for touch pressure and pain these are called

The correct answer is mechanoreceptors.  

The mechanoreceptors refer to the receptors, which instructs the CNS about the sensations of vibration, touch, and skin tension. They are sensitive to the mechanical distortions of the skin stimulated by coming in exposure with the objects.  

They are situated at the origin of the exteroreceptive sensitivity epicritic touch and permits the analysis and exploration of the external surrounding. They possess high sensitivity and are associated with the fast-conductive large sized myelinated fibers.  

oxygen = 21% of the atmosphere

nitrogen = 78%

carbon dioxide = 0.1%

argon =0.934%