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.
At a glance this one's confusing, I agree.
Genetic engineering has made it easier for forensic scientists to differentiate human DNA beyond simple blood sampling. This inevitable led to release of innocent accused prisoners.
the answer is the trophic level
A unicellular protist is a eukaryotic cell because it has a nucleus enclosed by a membrane. Protist cannont be grouped with plants, animals or fungi. However they are still eukaryotic.
Answer:ABCD
Explanation:
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