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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Though there's no question in the statement above I would assume that you are asking about the pH of the water that is acidic. The correct statement would be:
Any liquid that has a pH less than 7 is called acidic, a pH above 7 is basic or alkaline.
The water in the swimming pool has a high acid concentration due to the chlorine which causes the effect of redness in the eyes.
Answer: repel forces and attract forces
The correct option is D. all of the above