Of the us adult population, the proportion that has flown is:

Which heredity condition causes a buildup of mucus in lungs and pancreas? a. cystic fibrosis b. heart disease c. huntington's disease d. sickle cell anemia

Veins have a much lower blood pressure than arteries. which of these prevents backflow of blood in veins? a. pressure applied by the heart b. one–way valves in veins c. thin muscular walls of veins

Which of the following is a limitation of a clinical trial? a.)amount of random assignments b.)hospital cost c.)number of test tubes d.)amount of peer review