<span>C. Weathering breaks down rock and other material</span>
Regurgitation influences the flow of blood by mixing the oxygen-poor blood with the oxygen-rich blood. Due to this, the heart has to pump more to oxygenate the entire body, leading to the rapid, and fluttering heartbeat. The tissues get oxygenated but regurgitation could be fatal, as the heart cannot function overtime forever.
Valve prolapse influences the flow of blood when the flow of blood backs up. This leads to an irregular or racing heartbeat. Even at certain occasions, the blood can flow back to the lungs. However, there is not a huge influence in the oxygenation of the body tissues.
Stenosis makes the ventricles to pump overtime to get enough blood through, and in the process, the ventricles thicken. This functions for a while, however, it will result in heart failure as the heart cannot do it for entire life. The tissues are oxygenated, but it will be an issue due to overtime.
The answer is (C) Replication
Though occasional errors could occur in cells during replication; the cells have error checking and proofing mechanisms that reduce the rate of error to one to several million replications in higher eukaryotes.
After all, one mismatch error during replication would not result in major effects. The others choices, however, have higher rates of causing genetic abnormalities.
After the adenylyl cyclase reaction (which convert ATP into cyclic adenosine monophosphate-cAMP), cAMP level is directly increased. Next steps of PKA activation include:
• cAMP binding to regulatory subunits of PKA, as a result conformational change in the regulatory subunits of PKA is induced,
• catalytic subunits are detached and unleashed by regulatory subunits and as a result activated.
