Answer: (A) Acting as enzymes and structural molecules
Explanation: Proteins play a crucial role in the body by functioning as enzymes, which accelerate chemical reactions, and as structural molecules, contributing to the support and shape of cells and tissues.

Answer: (B) Protiens
Explanation: Enzymes are biological catalysts that speed up chemical reactions in the body, and they are composed of proteins. Proteins are responsible for various functions including enzyme activity, structural support, and transport in cells.

Answer: (D) Peptide bond
Explanation: A peptide bond is a covalent bond formed between the carboxyl group of one amino acid and the amino group of another, releasing a molecule of water. This bond is essential for forming the primary structure of proteins.

Answer: (B) Triglyceride
Explanation: Triglycerides are a type of lipid, which are fat molecules used for long-term energy storage in the body. Glucose and starch are carbohydrates, and glycogen is a form of carbohydrate storage.

Answer: (A) Nucleotides
Explanation: : Nucleic acids, such as DNA and RNA, are polymers composed of repeating units called nucleotides. Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base.

Answer: (C) Enabling biochemical reactions
Explanation:  Lipids are primarily involved in energy storage, insulation, and forming cell membranes. They do not catalyze biochemical reactions, a role typically fulfilled by enzymes.

Answer: (C) Carbohydrates
Explanation: Carbohydrates are the body’s primary source of energy. They are broken down into glucose, which is used by cells for fuel.

Answer: (D) Lactose
Explanation: Lactose is a disaccharide because it is composed of two sugar molecules (glucose and galactose) linked together. Glucose is a monosaccharide, while cellulose and starch are polysaccharides.

Answer: (A) Nucleic Acid
Explanation: Nucleic acids, including DNA and RNA, are responsible for storing and transmitting genetic information in living organisms. They are the fundamental molecules involved in heredity and cell function, unlike lipids, carbohydrates, or proteins which serve different biological roles.

Answer: (D) Hemoglobin
Explanation: Hemoglobin is a protein found in red blood cells that binds to oxygen and carries it from the lungs to the rest of the body. Insulin and glucagon are hormones involved in regulating blood sugar, and collagen is a structural protein found in connective tissues.