Where might a spring form?

between the saturated and unsaturated zones
at the bottom of a deep valley
on a mountaintop at the origin of a stream
on the surface of a fast-moving aquifer

answer:

these aquifers are underneath permeable soil layers, so water easily trickles through the ground into the aquifer. a spring is formed when the pressure in an aquifer causes some of the water to flow out at the surface. this usually happens at low elevations, along hillsides or at the bottom of slopes.

explanation:

i think its white blood cells

i hope this