How does scratching a person's back them go to sleep?
and why do most people like it when you scratch their back? along with bears, etc.

Which of the following is the most likely outcome of global warming

What is the main function of the central vacuole in a plant cell? a. absorbs energy from the sun to produce food b. holds water and maintains turgor pressure c. breaks down molecules to release energy d. contains the cell's genetic material

Explain how the parts of the peripheral nervous system work with the central nervous system to produce a response to the stimulus