When you see water at the bottom of the hole, that is a sign you've found Water Table
Water table refer to an area in the ground that are filled with water. Back in the day, before the modern watering system, people get their water supply by digging the ground until they fount water table and build a well around it
The Midwest is the biggest agricultural region in the United States, and of the biggest in the world. It is a region that has specialized in the production of several crops that are highly demanded on the market, and are used for multiple different things.
The reason why the Midwest has became an agricultural center is that it has very deep and highly fertile soil. The soil is of such a good quality because naturally this region is a grassland, so the enormous amounts of decaying grasses have created a very good soil suitable for growing numerous types of plants.
Unfortunately, converting the region into an agricultural center has caused lot of environmental problems. The grasslands have mostly been destroyed, and with it the habitat of lot of animals. The extensive usage of pesticides and other chemicals has resulted in pollution of the waters. The mechanization used in the agriculture has become one of the major contributors to the greenhouse gases emissions. Because big portion of the region is semi-arid, or only gets sufficient amounts of rainfall seasonally, the aquifers have been depleted.
The answer is D- study of maps
What are the following countries or nations?
