A seesaw is an example of a first class lever The fulcrum, which is the part of the lever that does not move, is in the middle. The resistance, which is the weight (person) you are trying to lift is at one end. The effort, which is the force applied to the lever, is the person sitting on the other end.
A seesaw is an example of a first class lever The fulcrum, which is the part of the lever that does not move, is in the middle. The resistance, which is the weight (person) you are trying to lift is at one end. The effort, which is the force applied to the lever, is the person sitting on the other end.
I believe it's the last two. "makes the lungs able to fill more completely" and "helps the blood vessels dilate more easily" hope this helps, have an amazing day :)
in controlled experiment an independent variable is systematically manupulated and dependent variable is measured ; any extraneous variables are controlled