An investigation was conducted using three groups of laboratory X, Y, and Z, to determine the relative effects of glucose and adrenaline on the rate of heartbeat. The experimental conditions for each group of rats were kept the same excerpt for the type of solution injected, as shown in the data table below. According to the data table, which group of rats functioned as the control

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