The four main sources of drugs are ____________________________________________, ____________________________________________, ____________________________________________, and ____________________________________________

Teeth are harder than bone

Indicate whether the statement is true or false

The best way to measure your achievement in your studies is to a. compare your performance to that of your classmates

b. evaluate your progress toward your goal of becoming a qualified health care professional. c. keep track of your grades. d. compare the "you" of today with the "you" of yesterday, last month, or last term. e. both b and d