Why is understanding the concept of forces, friction and gravity important?

Protons and neutrons are found within the nucleus of an atom

Each neuron shown in this figure innervates a group of muscle fibers. what is the term for a group of muscle fibers innervated by a single neuron?

In the illustration, which two simple machines are being used to enable the student to reach the door? a. inclined plane and pulley b lever and wheel-and-axle c pulley and lever d wheel-and axle and inclined plane