In digestion, proteins are broken down into smaller molecules for absorption into the bloodstream. The correct answer is option 3: amino acids. Amino acids are the building blocks of proteins. During digestion, proteins are broken apart by enzymes into their individual amino acid components. These amino acids are then absorbed into the bloodstream through the intestinal lining and transported to various cells in the body, where they are used for various purposes such as building and repairing tissues, producing enzymes and hormones, and supporting the immune system. It is important to note that proteins cannot be directly converted into fatty acids, glucose, or maltose during digestion. Instead, these molecules are produced through the digestion and absorption processes of other macronutrients like carbohydrates and fats.