Who is the first person to observe dead cells

If the atomic mass of an atom is 34 and the atom contains 13 protons, how many neutrons does the atom contain?

For ai it's atomic number is 13 and it's mass number is 27 how many neutrons does it have

Aradio signal from a gps satellite take only about 0.067 seconds to reach a gps reciever. if the speed of light is about 300,000km/s, then approximately how far away is the reciever from from the satellite?