Final answer:
When two glucose molecules join together, a disaccharide is formed through a dehydration reaction, creating a glycosidic bond.
Step-by-step explanation:
When two glucose (monosaccharides) molecules join together, A) A disaccharide is formed. This occurs through a process called a dehydration reaction or condensation reaction, where the hydroxyl group (-OH) of one glucose molecule combines with the hydrogen (H) from another, releasing a molecule of water (H₂O) and creating a covalent bond known as a glycosidic bond. For example, when two glucose molecules join, they form maltose, which is a type of disaccharide.