According to the Big Bang theory, the universe was once very dense and is now expanding.
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.
The answer is C. Enzymes lower activation energy, allowing the reaction to happen more quickly, which is why they are called catalysts.
