Answer:
A. 70
Explanation:
The mass of the atom is determined by the protons and the neutrons. Since the proton mass is 35 and the neutron mass is 35, all you need to do is add them up together:
35 + 35 = 70 amu
The electron's mass is considered negligible because it is still too small to determine. So the estimated mass of the atom will be based on the neutrons and the protons.
