D) The AV valves are supported by chordae tendineae so that they do not blow back up into the atria during ventricular contraction.
Answer:
In my opinion ...it is option A:)
Answer:
I believe it is A, but I could be wrong.
Explanation:
I think this, because when it says, "Other, less useful, versions of the genetic code were eliminated gradually throughout the course of evolution", I think it referencing to the fact that all animals and etc, are made up of common codes, and how over time, through evolution, certain codes were eliminated, because creatures were evolving.
It is known as stimulus or the plural form stimuli. It can be external or internal.
