After the arrival of hunter-gatherers in the southwestern region of North America, several alternative types of agriculture emerged, all involving different solutions to the Southwest’s fundamental problem: how to obtain enough water to grow crops in an environment in which rainfall is so low and unpredictable that little or no farming is practiced there today. People experimented with alternative strategies for almost a thousand years in different locations, and many experiments succeeded for centuries, but eventually all except one succumbed to environmental problems caused by human impact or climate change.
One strategy was to live at higher elevations where rainfall was higher, as did the Mogollon, the people at Mesa Verde, and the people of the early agricultural phase at Chaco Canyon known as the Pueblo I phase. But that carried a risk, because it is cooler at high than at low elevations, and in an especially cool year, it might be too cold to grow crops at all. An opposite extreme was to farm at the warmer low elevations, but there the rainfall is insufficient even for dryland agriculture. The Hohokam got around that problem by constructing the most extreme irrigation system in the Americas outside Peru. But irrigation entailed the risk that human digging of ditches and canals could lead to sudden heavy water runoff from rainstorms, digging further down into the ditches and canals and carving out deep channels called arroyos. In that case, the water level would drop below the field level, making irrigation impossible for people without pumps.
A more conservative strategy was to plant crops only in areas with reliable springs and groundwater tables. That was the solution initially adopted by the Mimbres and by people in the phase known as Pueblo II. However, it then became dangerously tempting to expand agriculture during wet decades with favorable growing conditions into marginal areas with less reliable springs and groundwater. The population multiplying in those marginal areas might then find itself unable to grow crops and might starve when the unpredictable climate turned dry again. That fate actually befell the Mimbres, who started by farming the floodplain and then began to farm adjacent land above the floodplain as their population came to exceed the floodplain’s capacity to support it. They got away with their gamble during a wet climate phase, when they were able to obtain half their food outside the floodplain. However, when drought conditions returned, that gamble left them with a population double what the floodplain could support, and Mimbres society collapsed suddenly under the stress.
Still another solution was to occupy an area only for a few decades, until the area’s soil became exhausted, then to move to another area. That method worked when people were living at low population densities, when there were many unoccupied areas to move to, and when each occupied area could be left unoccupied again for sufficiently long after occupation so that its vegetation and soil nutrients had time to recover. However, the method of shifting sites after a short occupation became impossible at high population densities, when people filled up the whole landscape and there was nowhere left empty to move to.
One more strategy was to plant crops at many sites even though rainfall was locally unpredictable and then to harvest crops at whichever sites did get enough rain to produce a good harvest and to redistribute some of the harvest to the people still living at all the sites that did not happen to receive enough rain that year. But redistribution was not without risks because it involved a complex political and social system to integrate activities between different sites, so when that complex system collapsed, lots of people ended up starving.
The remaining strategy was to plant crops and live near permanent or dependable sources of water, but on landscape benches above the main floodways, so as to avoid the risk of a heavy flood washing out fields and villages, and to practice a diverse economy, exploiting ecologically diverse zones so that each settlement would be self-sufficient. That solution, adopted by people whose descendents live today in the Southwest’s Hopi and Zuni villages, has succeeded for more than a thousand years.
1. The word ―eventually‖ in the passage is closet in meaning to
A. to some degree
C. in the end
2. Paragraph 1 supports which of the following inferences about the North American Southwest?
A.Its sources of water were plentiful when the hunter-gathers first arrived.
B. It has always lacked the large population needed to perform successful experiments in agriculture.
C. Its climatic conditions today are essentially similar to those existing when the hunter-gathers first arrived.
D. It was more seriously affected by climate change than it was by human impact.
3. All of the following are mentioned in paragraph 2 as potential problems faced by the Hohokam EXCEPT
A.insufficient rainfall to allow crops to grow
B. rainstorms leading to destructive water runoff
C. insufficient workers to dig ditches and canals
D. irrigation water levels in channels too low to be used
4. The word ―initially‖ in the passage is closet in meaning to
5. The word ―adjacent‖ in the passage is closet in meaning to
6. According to paragraph 3, which of the following was the cause of the collapse of the Mimbres society?
A.They could not overcome the stress of moving to a new area with each change in the climate.
B. The flooding of their farmland during a wet climate phase prevented them from growing enough to feed their population.
C. A decline in population during dry periods prevented them from expanding their farming into nearby areas.
D. Their population became too large to survive when the climate entered a dry period.
7. According to paragraph 4, the solution of moving to other, previously occupied areas was effective only when
A.the soil on the previously occupied land had been used for farming at least once
B. the vegetation and nutrients of the previously occupied area had time to recover
C. the reoccupations did not last a long time
D. the reoccupied areas became more densely populated
8. The solution for unpredictable rainfall described in paragraph 5 involved all of the following EXCEPT
A. planting crops in many different places, regardless of predicted rainfall
B. using a simple political and social system for the coordination of agricultural activities
C. harvesting crops from those sites that did receive adequate rain
D.sharing harvested crops with people whose crops did not grow well
9. The word ―dependable‖ in the passage is closet in meaning to
10. Which of the following contributed to the success of the strategy discussed in paragraph 6?
A.Crops were planted high enough to avoid being carried away by floods.
B. Crops were planted wherever there were sources of water, regardless of their proximity to where people actually lived.
C. Farming was limited to ecological zones that were similar to each other.
D. Instead of aiming at becoming self-sufficient, each village became part of a network of diverse economic activities.
11. Which of the following best describes the organization of the passage?
A.A historical account of the various people that have lived in southwestern North America followed by conflicting views about the accuracy of the account
B. A comparison and contrast of the historical role of agriculture in different parts of the southwestern region of North America
C. An explanation of how the solutions developed to improve living conditions in southwestern North America spread to other neighboring regions
D.A description of a long-standing problem faced by the people in southwestern North America followed by a discussion on strategies that have been used to overcome the problem
Paragraph 2 One strategy was to live at higher elevations where rainfall was higher, as did the Mogollon, the people at Mesa Verde, and the people of the early agricultural phase at Chaco Canyon known as the Pueblo I phase. But that carried a risk, because it is cooler at high than at low elevations, and in an especially cool year, it might be too cold to grow crops at all. An opposite extreme was to farm at the warmer low elevations, but there the rainfall is insufficient even for dryland agriculture. ■ The Hohokam got around that problem by constructing the most extreme irrigation system in the Americas outside Peru. ■ But irrigation entailed the risk that human digging of ditches and canals could lead to sudden heavy water runoff from rainstorms, digging further down into the ditches and canals and carving out deep channels called arroyos. ■ In that case, the water level would drop below the field level, making irrigation impossible for people without pumps. ■
12. Look at the four squares [■] that indicate where the following sentence can be added to the passage.
Another risk of irrigation was that floods could simply wash away the dams and channels, as indeed may have happened eventually to the Hohokam.
Where would the sentence best fit? Click on a square [■] to add the sentence to the passage.
13. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some answer choices do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.
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People trying to grow crops in the dry southwestern area of North America experimented with various strategies for almost a thousand years. ● ● ●
1.Experiments in agriculture succeeded in those areas that experienced climate changes that increased the amount of rainfall gradually over many centuries.
2.In spite of usually dry conditions, water runoff from rainstorms was used by the Hohokam to flood fields and deepen channels in irrigation systems.
3.Shifting sites or planting in areas with good sources of water was successful only in areas with low population densities.
4.Farming at higher elevations meant risking failure from cold weather, while extensive irrigation at the lower elevations risked destructive floods from sudden rainstorms.
5.Farming in dry climate phases was successful only at higher elevations.
6.Sharing food produced at different sites had limited success, while self-sufficient and ecologically sound farming continued to succeed.