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.
Group 13-17 contains metalloids. Boron, Silicon germanium, Arsenic, Antimony, Tellurium and Polonium are considered metalloids. They have properties of both metal and non metal. Some of the element are good semi-conductors .
Rose bush because not many animals eat rose bushes
