Answer: b) 400-600 IU
Lipids (fats) yield 9 kilocalories (kcal) per gram , making them the most energy-dense macronutrient. Both carbohydrates and proteins provide 4 kcal per gram, while water provides 0 kcal per gram. 2. Correct Answer: B) Glycogen
Explanation: Free radicals are unstable molecules that damage cell membranes and DNA. Antioxidants neutralize them.