How is the sense of touch different from the other senses?

Touch is, in several ways, seemingly different from these other senses, however. For one thing, touch does not seem to have a single sense organ. ... Instead, the skin contains many different sensory systems. Many of them, like those that code for pain and itch, do not seem to be tied directly to the sense of touch.

Explanation:

Touch is often classified as one of the traditional five senses, along with sight, hearing, smell, and taste. Touch is, in several ways, seemingly different from these other senses, however. For one thing, touch does not seem to have a single sense organ. ... Instead, the skin contains many different sensory system

the most logical answer would be a

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.