2.1.4 Monosacchrides containing four, five, and six carbon atoms in their backbones are called tetroses, pentoses(e.g, ribose and deoxyribose), and hexoses(e.g, glucose and fructose), respectively. Each has both aldoses and ketoses 2.1.5 Hexoses are the most common monosacchrides in nature, including D-glucose, D-mannose, D-galactose, D-fructose.2.1.4 Monosacchrides containing four, five, and six carbon atoms in their backbones are called tetroses, pentoses (e.g., ribose and deoxyribose), and hexoses (e.g., glucose and fructose), respectively. Each has both aldoses and ketoses. 2.1.5 Hexoses are the most common monosacchrides in nature, including D-glucose, D-mannose, D-galactose, D-fructose