The number of people per unit of arable land is called this.
What is physiological density?
The northern tropic name at 23° N. boundary of the subtropic zone north of the equator. There is also another tropic south of the equator 23° South. Between these latitudes is the famed tropics and subtropic climates.
What is tropic of Cancer?
Cereal grains such as wheat, barley, rye, are grasses which have edible grains. Identify another popular grass grain that can be consumed.
What are rice, sugarcane, millet, quinoa sorghum, oats, and maize (corn)?
The purpose and significance of the mechanized steel plow during the 2nd agricultural revolution, 19th century.
What is telling or clearing prairie steppe grass land?
Beginning around the middle of the 20th century modern methods in agriculture diffused to less developed countries. This period in agriculture is called this. 
What is the Green Revolution?
This system of agriculture requires high inputs (labor and capital) and produces high yields which drives global food production.
What is intensive agriculture?
The climate zones illustrated on this map. Agriculture production primarily includes coffee, cacao, tea, coconuts, bananas 
What is tropical and subtropical climate?
These two trade routes led to the diffusion of plants and animals in the Eastern hemisphere (old world). One is by land the other by sea. 
What are the silk road and Indian Ocean trade?
This technology related revolution coincided with the 2nd agricultural revolution. It allowed for machines and mechanization to help increase food production. 
What is the industrial revolution?
The genes of plants are changed and modified to improve quality and quantities, it is known as this.
What are Genetically Modified Organisms (GMO)?
This region/climate type in southern Europe supports the production of olives, grapes and dates.
What is Mediterranean climate?
Identify 4 of the earliest hearths of the agricultural revolution beginning nearly 12,000 years ago. 
What are Mesoamerica (Mayans), Fertile crescent (Mesopotamia), Indus River Valley, and China
This survey method is characterized by orderly, geometric boundaries mostly found in the Western part of the U.S. 
What is township and range?
This product of the 2nd agricultural revolution increased food production by reducing the time needed to harvest. 
What is a reaper harvester?
This cross-breeding of plants allows shot growing periods and crops to have superior characteristics such as resistant to certain pests.
This rural survey method is characterized by irregular shapes often using artificial landmarks such as a grain silo or barn to determine property lines.
What is metes and bounds?
The Great plains region, with steppe, and fields of grasses will likely be involved in this agricultural activity. Bison once roamed this semi-arid region.
What is cattle ranching or grazing livestock?
This rural survey method allows ease of access to a road or waterway. Makes trade efficient. 
What is long lot?
The population shifted from rural to this particularly in cities where factories which produced agriculture machines.
What is urban?
What are insecticide and herbicide?
The agricultural hearth location of wheat, rye, domesticated cattle, pigs, goats, and sheep which later diffused to farms and ranches across the U.S and beyond.
What is Fertile Crescent upper Mesopotamia?
Which agricultural hearth is responsible for diffusing squash, maize, and potatoes, beans, and tomatoes becoming global food staples.
What is Mesoamerica / Central America?
The intentional and repetitive behavior which cultivates a person's perceived coolness and/or confidence to gain status.
What is aura farming?
The benefits of the 2nd agricultural revolution include: Increase food production and this other factor which is related to the fact that there is food available. 
What is higher life expectancy?