Saccharides are a former generic name of carbohydrates.Carbohydrates are the fuel of the body: they are our main source of energy.On the other hand, unlike proteins and lipids, they are not essential nutrients, since our body knows how to make them from other nutrients.
ABOUT THE EXERCISE:
-The first proposition is false because: Maltose = glucose + glucose
-The second proposition is correct, Sucrose is also called table sugar (it is the that are used for pastry and bakery
-The third proposition is false because glycogen is a polysaccharide
-The fourth proposition is false too, the correct equation is glucose + galactose yields lactose.