Consider statements about human nutrition: 1. Essential amino acids cannot be synthesized by the body. 2. Saturated fats are liquid at room temperature. 3. Dietary fiber aids in digestion. Which are correct? MCQ with Answer and Explanation

Essential amino acids (like lysine, tryptophan) cannot be synthesized by the human body and must be obtained through the diet. Dietary fiber (roughage) is indigestible plant material that adds bulk to stool, promotes peristalsis, and aids in digestion and preventing constipation. Saturated fats have no double bonds between carbon atoms, making them solid at room temperature (like butter); unsaturated fats are liquid (like oils). Thus, statements 1 and 3 are correct.