All you need to look through the human body systems you had in the unit and explain how they make you living, rather than dead. What body systems do you have that make you a living human being. 1. Your Cardiovascular system. It keeps your body and cells supplied with oxygen so they can stay alive. 2. Your nervous system. It allows your body to take outside stimuli and allow your brain to process and react to it. 3. Your Digestive system. It allows you to extract the energy from other living things and use it to power your body.
Im not sure but if you think of it, the one that you didn't put any salt is a independent variable because it doesn't really rely on anything it doesn't have salt. The Dependent variable would be the 2nd and the 3rd cup because it doesn't have much salt but the 4th cup has lots of salt so its basically controlled. Hope it helps !
