a paragraph each about bones and muscles, the respiratory system, senses, and nutrition. I need help please help me lol.

What are your thoughts on nonhuman trials? do you feel that testing should be done on animals? what are the advantages and disadvantages with nonhuman trails?

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.

Being prepared to play is an important step in staying safe when participating in a game. select the best answer from the choices provided. t f