What are convection currents in the mantle caused by? A. The core heats up magma and increases its density, so it rises,
B. The core heats up magma and decreases its density, so it rises,
C. The core cools down magma and increases its density, so it rises,
D. The core cools down magma and decreases its density, so it rises.

The famous scientist galileo galilei did several experiments with sloping planes, which he rolled metal balls down so that he could study motion. by changing the slope, he could study how the speed at which the ball rolled was affected. what was the independent variable in galileo's experiment? a. the speed of the ball b. the slope of the plane c. whether the ball moved d. what the ball was made of