Scientists use models to him study systems in nature such as predicting the paths of hurricanes, demonstrating how cell organelles work, or determining the effect building a dam would have on the local ecosystem explain why models are used in science. !

In financial aspects, a depression is a sustained, long haul downturn in monetary movement in one or more economies. it is a more extreme monetary downturn than a recession, which is a slowdown in financial action through the span of a typical business cycle. a depression is an irregular and extreme type of recession. so depression is always followed by recession but it is not correct to state that a depression always follow a recession.