Think about a time when you saw a baby animal, such as a puppy or kitten. Think about the traits it inherited from its parents. How could you determine which traits were dominant and which where recessive? Discuss the question with a classmate and record your ideas in your science notebook.

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