D) The AV valves are supported by chordae tendineae so that they do not blow back up into the atria during ventricular contraction.
The main reason is that there is no atmosphere. This means that there is no weather and no weather means that there is no wind or rain. Wind and rain are main components of erosion and because there is no erosion, craters can stay preserved for a very long time.
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Answer: honestly i just dont know im here for the points thanks broski
Explanation: