An aquifer has been compared to a sponge. Think about this analogy for a moment explain why the use of the word quotations "sponge" is more appropriate in the use of "underground river" quotes to describe aquifers.

The word sponge is more appropriate to use than Underground river since an underground river can loose water while an aquifer cannot loose water, unless it is open-air and above ground. then the aquifer would slowly loose water due to evaporation from the sun.