Choose the true statement from the list below.

a) constructive and destructive processes never happen together.

b) weathering is the process where new land is formed.

c) weathering is the breaking down of rock and erosion is the movement of the smaller pieces.

d) weathering and erosion are two words for the same proces

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