What was the name of an ancient written work by the chinese that included the study of dentistry?
a. canon of medicine
b. the works of sir john tomes
c. hippocratic method
d. on medicine

Is the weather changing? consider the data of severe weather that includes tornadoes occurring throughout the u. s. over the last four years. compare the severe weather for the last three years. then compare the first three months of 2017 with that data. based on previous years, what might the prediction be for weather during 2017?