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.
It would be an oncogene, these can be inherited mutations of proto-oncogenes that cause the oncogene.
The answer is <span>c. Cold and flu season occurs when the weather is cold, so there must be a connection.
Even though choices a. and b. could make sense, nothing in Joel's research implies the connection between the choices and cold. Therefore, this leaves choice c. as the right one. If cold and flu season occurs</span><span> when the weather is cold, there must be a connection between cold and cold weather.</span>
CO2molecule is a reactant in the first step and a final product in the fourth step of the Calvin-benson
