This Problem Set is a part of the Lesson 2, Unit 3, Grade 6. Select the unit from the list that you would use to measure each object: The length of a pencil The weight or mass of a pencil, The volume of a pencil, The weight or mass of a hippopotamus, The length of a hippopotamus, The length of a fingernail clipping, The weight or mass of a fingernail clipping, The volume of a sink.