Abirds breastbone has a ridge called the

What process occurs during cellular development as the cell changes into a specific type of cell with specialized functions? a. binary fission b. fusion c. differentiation d. meiosis

The effect of a hormone on a target cell may be decreased by the presence of

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