Answer:
numer 1:Neutrons are required for the stability of nuclei, with the exception of the single-proton hydrogen nucleus. Neutrons are produced copiously in nuclear fission and fusion. They are a primary contributor to the nucleosynthesis of chemical elements within stars through fission, fusion, and neutron capture processes.
number 2:The number of neutrons is equal to the difference between the mass number of the atom (M) and the atomic number (Z).let me know if i helped