Have your teacher initial next to each piece of equipment as you demonstrate its proper use. Lactose sugar is a disaccharide, two rings big. To digest it, you need to break it down into two pieces, two monosaccharides. Lactase enzyme allows you to do this. It reduces the amount of energy needed for the hydrolysis of the disaccharide into two monosaccharides.
Enzymes are proteins.
Temperature can effect them. If you cook egg white protein, it changes from clear and runny to firm and white. It is denatured. Enzymes must fit with their substrate in order to work. If an enzyme is denatured, it cannot fit anymore.