“Topsoil erosion” refers to the gradual (or occasionally, rapid) depletion of the nutrient-rich topsoil in which almost all crops are grown. It is of such large concern because topsoil can take hundreds or thousands of years to replenish itself. Topsoil is found throughout the world and both the developed and developing world depend on crops grown in topsoil.

The Kyoto Protocol was signed in 1997 by more than 80 countries. This protocol's main goal was to reduce the emission of greenhouse gases (e.g., methane). The United States abandoned this protocol due to a fear of restricting growth.

Warmer sea surface temperatures, increases in sea level, and reduced biodiversity are all negative consequences of climate change. The ultimate cause of climate change is increased fossil fuel usage, which has negative implications for many aspects of life as we know it. 

The idea of environmental determinism states that the physical environment can direct human social development and culture towards certain patterns and trajectories. In other words, the physical environment can determine the fate of human culture to an extent. 

“Sharecropping” refers to a system of agriculture whereby a landowner allows an individual or a family to rent a portion of land in exchange for a share of the crops they harvest. “Serfdom” and “plantation” may seem like correct choices; however, “serfdom” refers to the status of many peasants under feudalistic rules that were considered to be part of the land that they farmed. “Plantation” refers to a large piece of land used to commercially produce a single crop.

A “polder” is a piece of farmland that has been reclaimed from water. They are usually from flooded plains, marshes, or—more recently—the sea. This is important for sustaining agricultural growth in regions of the world that are low-lying and easily flooded.

A “feedlot” is a place where a large quantity of livestock is raised in extremely cramped and inhumane, but cost effective, conditions. The factory farms where chickens are often produced in the United States are examples of “feedlots.”

“Crop rotation” is a system developed during the Second Agricultural Revolution in order to preserve the mineral health of soil used in agriculture and prevents patches of land from being exhausted. The idea is that by growing different crops, in the same soil, in the different seasons the soil can be preserved for a much longer period of time than it otherwise might be. The reasons for this are numerous and complicated, but the simplest explanation is that different crops drain the soil of different minerals and, additionally, replenish the soil with different nutrients.

“Spring wheat” is an extremely important collection of crops that provides a great deal of the nutrition that is consumed by the planet. “Spring wheat” is planted in early spring and usually harvested in the late summer. In the United States “spring wheat” is generally harvested between mid-August and late-September.

“Polders” have long been associated with the Netherlands. A “polder” is a piece of farming land that has been reclaimed from water, either from the sea or from flooded plains and marshes. It was particularly crucial in Dutch history due to the fact that the Netherlands is an extremely low-lying country with almost no elevated terrain above sea level.