What is Soil (and Why is it Important)?: Crash Course Geography #17

What was the primary cause of the Aral Sea's shrinking?

• Overfishing by local communities.

• Diversion of river water for irrigation.

• Natural climate change and drought.

• Increased industrial pollution.

What is salinization, as described in the video?

• The process of adding nutrients to soil to make it fertile.

• The buildup of salt in the soil, preventing plants from absorbing water and nutrients.

• The erosion of soil due to strong winds and dust storms.

• The natural process of water evaporating from a lake.

Which of the following are the four main components that make up soil?

• Rocks, sand, clay, and silt.

• Minerals, organic material, air, and water.

• Plants, animals, microbes, and sunlight.

• Humus, parent material, nutrients, and precipitation.

Which soil horizon is commonly known as topsoil and contains a lot of nutrients and decomposed organic material?

• O Horizon

• A Horizon

• E Horizon

• B Horizon

What is the lowest layer of the soil profile, made of unbroken parent material?

• O Horizon

• A Horizon

• C Horizon

• R Horizon

What percentage of farmlands are losing soil faster than new soil can form?

• 15 percent

• 25 percent

• 35 percent

• 50 percent

Which soil formation process occurs in tropical, moist climates where rocks break down rapidly and minerals decompose, forming iron-rich, brick-like soil?

• Calcification

• Podzolization

• Laterization

• Erosion

In climates with less moisture where grasses thrive, which process causes calcium carbonate to leach down and create a hard layer in the soil?

• Laterization

• Podzolization

• Calcification

• Weathering