Which of the following animals rely on symbiotic relationships with bacteria to obtain nutrients?

Most digestive enzymes function in the __________.

Pepsin is an enzyme produced in the stomach that attacks proteins to break them down into smaller peptide molecules. Which of the following statements about this enzyme is true?

The lungs consist of many small air sacs and blood vessels, which greatly increase surface area and improve the transfer of substances through their walls. The structures in the digestive system most similar in function to these air sacs and capillaries are the __________.

Gallstone surgery sometimes requires that the gallbladder be removed. Patients are then advised to avoid ingesting large amounts of fat because __________.

How would you expect the digestive system of a hawk to compare with that of a seed-eating sparrow?

Where does absorption take place in the small intestine?

Researchers provided radioactively labeled food to a dog and traced the movement of absorbed molecules. Which type of molecule moved along a path different from all the others?

The lymphatic vessels in the villi absorb and transport __________.