How does skin defend the body against pathogens? A. It destroys pathogens with digestive acids.
B. It produces white blood cells that attack pathogens.
C. It blocks pathogens from getting inside the body.
D. It uses tiny hairs to trap pathogens.

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