The spinal cord is part of the central nervous system

a)



b)


Using the atomic mass given in the periodic table:




c)


Using the atomic mass given in the periodic table:




This result is an aproximation.
Mass number is apart of (what ever subject it is)
Weight is the force exerted by the gravity on that object, therefore when an astronaut is in space with no gravity he is weightless. Mass is the actual amount of matter contained in a body, this won’t change if the gravity changes.