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.
Answer: Semi-conservative replication means that during DNA replication, the two strands of nucleotides separate. Both strands then form the template for free nucleotides to bind to to create the two identical daughter strands. Hence each daughter strand has half of the DNA from the original strand and half newly-formed DNA. brainliest
Explanation:
Salivary amylase will be active for only an hour or so because the optimum pH for activity of amylase is about 6.7–7.0 which is available in the mouth but the pH of the stomach is acidic around 1-2 due to which the amylase enzyme becomes inactive in short-time.
The lingual lipase enzyme is present in the saliva but isn't active until reaching the stomach because this enzyme is acid stable and works efficiently in the stomach, not in the mouth.
Amylase enzyme is secreted in the mouth and is responsible for the breakdown of starch in food into sugars and it starts acting as soon as we put food in the mouth whereas Lingual lipase enzyme is secreted along with saliva but it is not active in the mouth rather its activity starts in the stomach which is responsible for the degradation of triacylglycerol molecules.
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The answer to the question is enzyme linked receptor.
