It’s “c. +1” because the Sodium is losing a proton, which has a positive chage
MA= output force/input force
MA= 100N/20N
MA= 50
So you have to multiply 786,3 times 0.98 to get the mass the mass is 770.57 if u round its 770.6 or 771
population is the number of species living in a given area if this is regarding biology or earth studies :)