Respuesta :
					                   the 1st is correct and the 2nd is also correct as it should obey the Law of Conservation of mass.
					                
					                
					             
					                   The answer is A because a system is actually made up of different parts working together as one unit. A phone is an example of a system because it is made up of parts that work together such as the processer and graphics card. 
					                
					                
					             