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.

Answer: (B) Glucose
Explanation: Glucose is a simple sugar known as a monosaccharide, which is the most basic form of sugar. Glycogen and starch are polysaccharides, and sucrose is a disaccharide.

Answer: (C) Amino acids
Explanation: Proteins are made up of amino acids, which are organic compounds that serve as the building blocks for protein synthesis. Fatty acids are components of fats, nucleotides are the building blocks of nucleic acids (like DNA and RNA), and monosaccharides are simple sugars that form carbohydrates.

Answer: (A) Carbon, hydrogen, oxygen
Explanation:  Carbohydrates are organic compounds primarily composed of three elements: carbon, hydrogen, and oxygen, typically in a 1:2:1 ratio.

Answer: (B) Sugars
Explanation: Carbohydrates are primarily known as sugars because they consist of molecules like glucose, fructose, and sucrose, which are forms of simple and complex sugars that provide energy to the body.

Answer: (C) Monosaccharides
Explanation: Monosaccharides are the simplest form of carbohydrates, consisting of a single sugar unit, which cannot be broken down into smaller carbohydrates.

Answer: (A) Monosaccharides, Disaccharides, Polysaccharides
Explanation: Carbohydrates are classified based on the number of sugar units they contain: monosaccharides (single sugar), disaccharides (two sugars), and polysaccharides (many sugars).

Answer: (C) Sucrose
Explanation: Sucrose is a disaccharide because it is composed of two monosaccharides: glucose and fructose. Glucose and fructose are single sugar units (monosaccharides), while cellulose is a polysaccharide.

Answer: (C) Oligosaccharides
Explanation: Oligosaccharides are carbohydrates composed of 3 to 10 sugar units. Monosaccharides are single sugar units, disaccharides consist of two sugar units, and polysaccharides are long chains of sugar units.