How do villi present in the small intestine increase the absorption rate?

Which of the following are properties of mechanical waves? check all that apply ⭕️ particles of the medium move back and fourth, but do not move with the wave. ⭕️ the particles of the medium always move parallel to the wave motion. ⭕️ wave motion begins with a disturbance in the medium. ⭕️ waves transport energy from a source outward, away from the source.

What causes the formation of ocean currents?

When solid surfaces slide over each other the kind of friction that occurs is called friction