PLEASE HELPPP What type of signaling is represented in the figure?

Radiometric dating is used to tell the absolute age of materials by studying the decay rate of radioactive isotopes. the decay rates of isotopes are constant and are expressed as .

Which best describes how sediment forms? loose material is cemented by pressure. erosion breaks down rock and other material. molten rock cools above earth's surface. chemical changes cause sediment to compact together.

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