Hydrochloric acid (HCI) is secreted from?

A. Amino acids; proteins: Amino acids are the end products of protein digestion, not the substrates that are broken down.

B. Polysaccharides; amino acids: Polysaccharides are broken down into simple sugars (monosaccharides), not amino acids.

C. Proteins; nucleotides: Proteins are broken down into amino acids, not nucleotides. Nucleotides are components of nucleic acids, not proteins.

D. Nucleic acids; nucleotides: Nucleic acids (such as DNA and RNA) are broken down into nucleotides.

A. Small intestine is the primary site of nutrient absorption. The majority of digestion and absorption of nutrients such as carbohydrates, proteins, and fats occurs in the small intestine, particularly in the duodenum and jejunum.

B. Pancreas secretes digestive enzymes into the small intestine but does not absorb nutrients itself.

C. Stomach plays a role in the digestion of proteins and the mechanical breakdown of food, but it absorbs very few nutrients, primarily alcohol and some drugs.

D. Large intestine absorbs water and electrolytes, but it is not the major site of nutrient absorption. Most nutrients are absorbed before food reaches the large intestine.