A region is an area with at least one feature that makes it different from other areas. E.g. Urban region, rural region, coastal region, desert region, Spanish-speaking region etc. A region may be large or small. The continent of North America is a region. The neighborhood where you live is a region, too.
Interdependence is the depending on one another for resources, products or services.
Political regions are a place where people share a government. Creating political regions helps people live an govern in an organized way. The United States has 3 levels of government - federal, state and local.
A physical region is an area based on NATURAL RESOURCES such as landforms, climate, natural vegetation, mountains and rivers.
An economic region is a region based on the way people in an area USE RESOURCES TO MEET THEIR NEEDS. E.g. Oil-producing region, agricultural region, manufacturing region etc.
A cultural region is an area in which people share certain ways of life such as religion, language, or the main ethnic group that lives there.