After traveling through the cecum, feces then travels through which of the following sections of the colon?

A. After passing through the proximal convoluted tubule, the filtrate enters the Loop of Henle, where further reabsorption of water and solutes occurs. This is the next step in the nephron's sequence.

B. The collecting duct comes much later in the nephron pathway, receiving filtrate after the distal convoluted tubule. It is not the immediate successor to the proximal convoluted tubule.

C. The glomerulus is the site where blood filtration begins, preceding the proximal convoluted tubule, so the filtrate does not return here.

D. Bowman's capsule collects the initial filtrate from the glomerulus before it enters the proximal convoluted tubule, making it an earlier step in the nephron process.

A. The kidneys do not play a role in the chemical breakdown of protein. Their primary function is filtration and regulation of blood composition.

B. The mouth is where mechanical digestion (chewing) occurs, but chemical digestion of proteins does not begin there. Enzymes like amylase break down carbohydrates, not proteins.

C. The stomach is where protein digestion begins. The enzyme pepsin, activated by stomach acid (HCl), starts breaking down proteins into smaller peptides. This is the correct answer.

D. The small intestine continues the digestion of proteins, but the initial breakdown occurs in the stomach. The pancreas also releases digestive enzymes, including trypsin, to further digest proteins in the small intestine.