Basically physical and chemical weathering (do not confuse with erosion, which involves movement) contribute to the destruction of mineral forms. In this case it breaks down the rocks, minerals and soils, creating slopes and hills. It may be caused by (any form of) water, wind, gravity, waves or sunlight.
The higher the population the more water is consumed. the Aquifer is depleted.
Market economies are based on market forces like supply and demand. Mixed economies fall in the middle of market and command economies (where economic choices are governed by some central entity usually the government). The former Soviet Union (USSR) is an example of a command economy where economic choices (what to buy, sell and produce) where made by the government. If Australia is becoming more of a market economy and less of a mixed economy, fewer decisions are made by the government. Here's a diagram of two major types of economies:
Command Economy <-------------- Mixed Economy --------> Market Economy
(Government makes the decisions) (A little of both) (Individuals decide)
Raw material Used to make steel
