sentences: comparing a property of different objects requires measuring that property for each object & mass is a property of objects ->  comparing the mass of different objects requires measuring the mass for each object  comparing the mass of different objects requires measuring the mass for each object & a balance is used for measuring the mass of an object ->  comparing the mass of different objects requires using a balance for each object  comparing the mass of different objects requires using a balance for each object & a potato slice is a kind of object -> comparing the mass of different potato slices requires using a balance for each potato slice