Q.

1. What are the components of balanced diet ?
2. Why is food cooked ? What is the difference in the physical states of uncooked and cooked food ?
3. What are the chemicals that we come across in everyday life ?

Step 1. Components of a balanced diet. Section 16.1 lists the nutrients food supplies: carbohydrates, lipids, proteins, vitamins, minerals and water -- a balanced diet is one that supplies all six in adequate proportion.

Step 2. Why food is cooked, and the physical-state difference. Cooking partially hydrolyses the large polymer molecules of protein and carbohydrate present in raw food into smaller polymer fragments. This changes the food's physical state: uncooked food is described as a heterogeneous suspension, while cooked food becomes a colloidal system. Because the resulting nutrient molecules are smaller, cooked food is easier for the body to digest.

Step 3. Everyday chemicals. Beyond the nutrients in food itself, the chapter goes on to cover food additives (antioxidants, preservative-type actions), medicinal drugs (analgesics, antimicrobials), and cleansing agents (soaps, detergents) as the three broad classes of 'chemicals we come across in everyday life'.

Direct recall of Section 16.1's nutrient list and the cooking/digestion explanation

• Omitting water and minerals from the six nutrient classes, listing only carbohydrates/proteins/fats/vitamins.
• Saying cooking simply 'kills germs' without connecting it to the actual chemistry described in the text -- polymer hydrolysis and the suspension-to-colloid change.