Complete 3 page APA formatted essay: Unit 7 paper biochem.As the extent and the strength of the exercises increases, the aerobic system (mitochondrial or oxidative system) takes over and provides the energy needed. Therefore, the first few minutes of running involve anaerobic activity, but as the intensity of the exercise increases during running and weight lifting,aerobic activity takes over to oxidise the previously produced pyruvate into more ATP to sustain the body during the exercise. These energy systems are interdependent of each other and work concurrently in the body.Based on the meal plan above, rice is the key carbohydrate food that is rich in starch. Skim milk, in addition, contains carbohydrates in the form of lactose (milk sugar). Beans also contain the polysaccharide starch. Protein foods include chicken, beans, and skim milk (whey proteins). Olive oil, skim milk, and ranch dressing contain fats. Olive oil, ranch salad, and chicken contain unsaturated fats, whereas skim milk contains exceptionally small quantities of saturated fats since skim milk usually has a low quantity of fat compared to whole milk. The salad contains vitamins, minerals, and roughage (fiber), which do not undergo digestion in the alimentary canal.When food is ingested in the mouth, the grinding action of the teeth (mechanical digestion) breaks it down into small pieces as saliva lubricates it. Chemical digestion of carbohydrates begins in the mouth where salivary amylase (ptyalin) digests starch into maltose. In the stomach, waves of muscular contractions called peristalsis (mechanical digestion) further squeeze the food, aiding in mechanical digestion. The gastric cells in the stomach walls secrete acidic juices including hydrochloric acid that create a favourable environment for the enzyme pepsin, which digests proteins into peptides. The partially digested food passes to the duodenum where most of the enzymatic digestion takes place.The pancreas