Definitions of food

Washing hands with clean water and soap before preparing or serving food is a basic food-safety practice. It removes dirt and reduces the transfer of harmful microorganisms from hands to food, utensils, and surfaces. Hand hygiene should also be practised after using the toilet, handling raw foods, coughing, or touching waste. The other options increase contamination risk. Therefore, option A is the correct simple rule.

Nutrients are useful chemical components of food that the body needs for energy, growth, repair, regulation and protection. Major nutrient groups include carbohydrates, proteins, fats, vitamins, minerals and water. Different foods supply these nutrients in different amounts, so a varied diet helps the body receive what it needs for normal health and development.

Food quality refers to the characteristics that make food suitable and desirable for consumption. It includes nutritional value, safety from harmful microorganisms and contaminants, freshness, appearance, taste, texture, and compliance with required standards. The colour of a plate or the cost of clothes has no relationship to food quality. Option B is correct because it captures the central nutritional and safety aspects, while also allowing for acceptability.

The primary functions of food are to provide energy, supply nutrients for growth and repair, and help protect and regulate body processes. Taste, colour, and appearance may make food attractive, but they are not its main biological functions. Therefore, option A gives the most complete answer.

Chewing mechanically breaks food into smaller pieces and mixes it with saliva. Saliva begins the digestion of starch and makes the food easier to swallow and process in the stomach and intestine. Chewing does not remove the need for water or eliminate energy; therefore, option A is the only correct answer.

Cooking for the required time with little water helps reduce the loss of water-soluble vitamins, especially vitamin C and some B vitamins. Excess water allows nutrients to leach out, while prolonged heating can destroy heat-sensitive vitamins. Using a covered pan and reusing safe cooking liquid can further conserve nutrients, so option B is correct.

Shelf life is the period during which food remains safe, reasonably nutritious, and acceptable in taste, smell, texture, and appearance when stored under suitable conditions. Increasing shelf life means slowing spoilage caused by microorganisms, enzymes, moisture, oxidation, or insects. Methods such as refrigeration, drying, canning, and suitable packaging can extend this period.