Final answer:
The true statement about digestion is that proteins are broken down into amino acids in the small intestine. The stomach and the small intestine are involved in the breakdown of proteins, whereas the actual absorption of nutrients primarily occurs in the small intestine through villi.
Step-by-step explanation:
True Statement about Digestion
The accurate statement about digestion among the given options is: Proteins are broken down into amino acids in the small intestine. While digestion begins in the mouth, where carbohydrates start to be broken down by the enzyme amylase, the main protein digestion occurs in the stomach, with the enzyme pepsin, and continues into the small intestine, where proteins are further broken down by enzymes like trypsin and chymotrypsin from the pancreas. Fats are primarily digested in the small intestine with the help of bile that emulsifies fats, and lipase enzymes that break them down. The small intestine is also the main site for the absorption of nutrients through villi. Mechanical digestion can occur in the large intestine with the help of bacterial processes, while wave-like muscle contractions known as peristalsis aid in moving semi-solid waste. Nutrient absorption does not occur in the esophagus, as its function is to transport food from the mouth to the stomach.