In a typical ECG (Electrocardiogram) the first wave obtained is P wave; The P wave represents the depolarization of the atria. After this, the QRS complex is formed. The QRS wave represents the depolarization of the ventricles. During the depolarization phase, the ventricles contracts and pushes the blood into the atria. Hence, the correct answer is depolarization of the ventricles.
Answer:
The outermost shell of a terrestrial planet is referred to as "crust." The Earth's crust is separated into two types: continental crust, which is older and thicker, and oceanic crust, which is younger and denser. Plate tectonics influences the dynamic geology of the Earth's crust. The outermost shell of a terrestrial planet is referred to as "crust."
The mantle is the layer immediately beneath the sima. With a thickness of 1800 miles, it is the Earth's thickest layer. The mantle is made up of extremely hot and thick rock. Under the weight of a huge load, this layer of granite even flows like asphalt. The flow is caused by large temperature differences between the mantle's bottom and top. The movement of the Earth's plates is due to the movement of the mantle! The mantle's temperature ranges from 1600 degrees Fahrenheit near the top to about 4000 degrees Fahrenheit near the bottom!
The two semilunar valves, the pulmonary and aortic valves, are closed, preventing backflow of blood into the right and left ventricles from the pulmonary trunk on the right and the aorta on the left.