How is absorption speeded up? is it something to do with villi?

What gases are carried by the blood

To take a whiff of your favorite food, you use both? a. motor nerves and your digestive system b. sensory nerves and your immune system c. motor nerves and your skeletal system d. sensory nerves and your respiratory system

Enzymes are both ph and temperature specific. seen here are the reaction rates of three common digestive enzymes. based on the data, which enzyme's optimum activity occurs in a basic environment while another's is very acidic?