Students are testing the james river for dissolved-oxygen levels. They test in the blue ridge mountains, at the rivers source, and in Richmond Virginia, a highly populated area. What is the independent variable in this experiment?

very

for example, no new evidence will demonstrate that the earth does not orbit around the sun (heliocentric theory), or that living things are not made of cells (cell theory), that matter is not composed of atoms, or that the surface of the earth is not divided into solid plates that have moved over geological timescales .