Answer:
120 Kcal
Explanation:
The process of cellular respiration produces energy using the carbohydrate as substrate but it also uses proteins and fats as the substrate.
1 gram of fat provides- 9 kcal therefore 20 g of fat will provide
20x 9= 180 kcal.
1 gram of carbohydrate provides- 4 kcal therefore 100 g of carbohydrate will provide
100 x 4 = 400 kcal.
1 gram of proteins provides-4 kcal therefore 20 g of protein will provide
30 x 4=120 kcal.
Thus, in question proteins will provide 120 kcal.