<span>Groundwater
Groundwater flows through rock with a high porosity and a high permeability at a fast rate. The denser and less permeable the rock is, the slower the groundwater moves. The greater the permeability of a rock, the faster the groundwater flows through it. Groundwater is water that is found in spaces and fractures in rocks, as well as in the sediment between the earth's surface. </span>
Predator-prey will be your answer
True.
It has been studied in a research study that claims birds have the ability and capability to regenerate their hair cells. This regeneration happens when the hair cells die but come back to its original form despite the damage it might have faced. Further, they can also regrow their hair cells in their ears.