What allows us to stand upright and keeps us from falling through the ground?

Ten students stand in a circle and are told to make a transverse wave. what best describes the motion of the students? each student bumps the shoulder of his or her neighbor. at the exact time, all students take a step to the right. the students skip clockwise, going in a circular motion. one at a time, each student lifts his or her hands up and then down.

If angle "a" is 25°, angle "b" is: a) equal to angle c b) less than angle c c) greater than angle c

Heterogeneous mixture with larger particles that never settle is