I need therapy. Also two paragraph.

Scientists must use microscopes to study the cells of living things. Microscopes have become much more powerful since scientists used them to develop the cell theory. Explain why microscopes are needed to study cells. Also describe some discoveries that microscopes have helped scientists make about cells. Include how advances in microscopes have helped scientists make these discoveries.

What component of fitt refers to the duration of a single workout?

What is the style of discipline in which the teacher or parent establishes rules, monitors the child's behavior, then enforced rules by administering appropriate punishment

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.