In a command economy, the government regulates economic activity, making decisions about what and how much to produce, where to locate economic activities, and what prices to charge for goods and services. These economic decisions are often made to further social goals. In a command economy, the price of goods including agricultural products are controlled by the government, not market forces. Production costs are not reflected in prices. The price also may be set over production costs given demand.
Profit drives decisions in a market economy.
A mixed economy combines elements of these three systems. El Ni o Southern Oscillation is a periodic, large-scale, abnormal warming of the sea surface in the low latitudes of the eastern Pacific Ocean that produces a temporary reversal of surface ocean currents and airflows through the equatorial Pacific. These regional events have global implications, disturbing normal weather patterns in many parts of the world. People elected as public officials are elected leaders. Students who are elected to their student government are elected leaders.