Aisha wonders whether wind or water causes the most erosion. She set up an experiment in which she used a watering can to pour water down a pile of dirt. She then used a fan to blow wind on a second pile of dirt that is the exact same shape and size as the first pile of dirt. Aisha then measured how the height of the dirt piles changed. She also drew pictures of how their shape changed. In this experiment, what was the outcome variable (dependent variable)? A.
the time the dirt piles were eroded away
B.
the agent of erosion applied to the dirt piles
C.
the tools used to measure the dirt piles
D.
the height and shape of the dirt piles