Organic substances derived from plants or animals, which are necessary for normal growth and development

The purity of ecstasy is always in question, why? (short answer)

What nutrients prevent osteoporosis? a. all vitamins and minerals b. calcium, vitamins c, d, and k, and magnesium c. protein d. carbohydrates

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.