Answer: D) Pulmonary and aortic valves.
Explanation
There are two main heartbeats from a healthy heart.
The first beat is called the S1 or the lub, and it occurs when the atrioventricular valves (comprising the mitral and tricuspid valves) close.
The second beat is called the S2 or the dub, and it occurs when the semilunar valves (comprising the aortic and pulmonary valves) close.
Listening for heart beats is an essential part of cardiac auscultation.
The westerlies wind from Mediterranean sea cause the more rainfall in winter in western part so winter crpos grow well in western part of nepal.
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B the origin of new matter in the steady state theory???
The 1883 eruption of Krakatoa (Indonesian: Krakatau ) in the Sunda Strait began on the afternoon of Sunday, 26 August 1883—with origins as early as May of that year—and peaked on the late morning of Monday, 27 August 1883, when over 70% of the island of Krakatoa and its surrounding archipelago were destroyed as it collapsed into a caldera.
