Answer: (D) Junk food
Explanation: A balanced diet includes essential nutrients like carbohydrates, proteins, and vitamins, while junk food is unhealthy and lacks nutritional value, thus not considered a part of a balanced diet.

Answer: (A) To build and repair tissues
Explanation: Proteins are essential for the growth, maintenance, and repair of body tissues. They are the building blocks for muscles, skin, and other organs, making them vital for overall body function.

Answer: (A) Carbohydrates
Explanation: Fat-soluble vitamins (A, D, E, K) are absorbed in the small intestine along with dietary fats. Without fats, these vitamins cannot be effectively absorbed into the body.

Answer: (C) It aids in regulating body temperature and supports bodily functions
Explanation: Water is essential because it helps regulate body temperature, transports nutrients, and is involved in many vital physiological processes required for overall health.

Answer: (B) To aid in digestion and prevent constipation
Explanation: Dietary fiber helps regulate the body’s digestive system by adding bulk to the stool, which eases bowel movements and helps prevent constipation. It does not provide energy or contribute to fat storage or muscle growth.

Answer: (C) Calcium
Explanation: Calcium is essential for bone and teeth formation. It helps maintain their structure and strength, supporting overall skeletal health.

Answer: (A) Help regulate metabolic processes
Explanation: Vitamins are essential micronutrients that help regulate metabolic processes, supporting various bodily functions such as energy production, immune response, and cell growth. They do not provide bulk, store nutrients, or act as a primary energy source.

Answer: (D) Plastic
Explanation: Biomolecules are organic molecules essential for life, such as carbohydrates, proteins, and lipids. Plastic is a synthetic material and does not occur naturally in living organisms, making it not a biomolecule.

Answer: (C) Carbon, Hydrogen, and Oxygen
Explanation: Carbohydrates are organic compounds made up of carbon (C), hydrogen (H), and oxygen (O), typically in a ratio of 1:2:1. These elements are fundamental to their structure and function.

Answer: (C) Cellulose
Explanation: Cellulose is a polysaccharide made up of long chains of glucose units, which is a structural component of plant cell walls. Glucose and fructose are monosaccharides, while sucrose is a disaccharide.