During the systole phase of the cardiac cycle , the left ventricle contracts and blood is pumped into the aorta. which of these valves prevents a back flow of blood into the left atrium

stimulus is a change in the environment that causes an organism to react. the response is the reaction to the stimulus. some examples of stimuli for zebras are drought, to many predators, and bad feeding grounds such as dead grass or plants. zebras respond to stimuli just like all other living organisms

mathematical model hope this