Earth and it's system and subsystem?

Question

The Earth system has an almost endless array of subsystems. In most natural systems, some of the mechanisms involved are positive feedback mechanisms, while others produce negative responses.

Consider the subsystems at work in and about you and your community. List and describe one example of a positive feedback mechanism and one example of a negative feed mechanism at work in these systems.

Answer 1

When I was a kid all the houses in the neighborhood had septic tanks with leech fields in their green yards.  There was plenty of water in the wells.  As the orchards were dug up to make room for more houses, the city sewer was extended out.  Now the yards are brown.  It seems that the aquifer is low and some wells are dry.  Where there used to be a water cycle the ground is now covered with pavement or buildings so that when it rains the water washes off and little sinks much past the surface.

Answer 2

Wow!  This seems like a homework assignment.  It is a great question but I have been out of school way too long for this type of deep studying.

Good luck though.