Answer: 1. Disaccharide
2. two monosaccharides, galactose and glucose
3. the role of lactase is to catalyse the hydrolysis of the disaccharide lactose to yield the monosaccharides galactose and glucose
Step-by-step explanation:
Lactose is a disaccharide, consisting of two monosaccharide units joined by a beta 1–>4 glycoside link
Lactase cleaves the glycoside link, giving two monosaccharides, galactose and glucose