No, because their job is to teach, and by giving you work and homework, they are making you review what you learn.
Also, they don't get payed enough- (sadly)
The smallest lake in africa is Lake Edward
Continental crust is 2.7-3.0
Oceanic crust is 3.0-3.3
Mantle is 3.3-5.7
Outer core is 9.9-12.2
Inner core is 12.6-13.0
