Which disadvantage is associated with nuclear energy? a. there is a very small amount of nuclear fuel. o b. the waste breaks down very quickly. o c. nuclear energy does not give off carbon dioxide. o d. the waste is hazardous and difficult to store.

1. beginning with all chambers of the heart in the "relaxed" phase, describe the cardiac cycle in mammals, with systole and diastole of the atria and ventricles. for each time point in the cycle you select, state the following: • whether the atria and ventricles are contracting or relaxing • whether the av valves and semilunar valves are closed or open • whether the pressure in the atria and ventricles is high or low