HELP PLEASE And comment if you are in connexus

Agas contained within a piston-cylinder assembly undergoes three processes in series: process 12: compression with pv= constant from 1 bar and 1 liter to 4 bar. process 23: constant pressure expansion to 1 liter. process 31: constant volume calculate the pressure and volume at each state, and sketch the processes on a p-vdiagram labeled with pressure and volume values at each numbered stat

Which best represents the law of conservation of mass ?

Aria drove to the store, did some shopping, and then came home. during maria's trip, when was her displacement equal to zero?