This graph shows the number of turtles living in a pond over time.

What happens to the number of turtles over these five years?

The number goes up.
The number goes down.
The number goes up and down.
The number stays the same.

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