There is little written in history books about public health problems and response, suggesting that these issues have had little impact on history. Consider the European colonization of the Americas, beginning in the 16th century. How was it possible for Cortez and other European figures to overcome immense Native American cultures with millions of people? What role, if any, did public health themes and issues play?

Check all that occur during ventricular systole. a. the av valves open to allow blood to enter the ventricles from the atria. b. the av valves open to allow blood to enter the ventricles from the atria. c. the semilunar valves remain closed throughout systole to prevent backflow of blood into the ventricles. d. the semilunar valves remain closed throughout systole to prevent backflow of blood into the ventricles. e. the semilunar valves open to allow blood to flow into the large arteries. f. the semilunar valves open to allow blood to flow into the large arteries. g. the av valves close to prevent backflow of blood into the atria.