A major problem facing industrial societies is their exponentially inc

So, the author’s Purpose is to describe the problems of deep-well injection.
The Main Idea is that industries continue to use deep-well injection to get rid of waste, but it’s a controversial and dangerous solution.
1. (D) Primary Purpose
Step 1: Identify the Question Type
The question asks for the “main point of the passage,” making this a Global question.
Step 2: Research the Relevant Text
All of the text is relevant to a Global question. Don’t reread the passage content. Instead, consider the Main Idea you distilled while reading the passage.
Step 3: Make a Prediction
The author’s Main Idea is that deep-well injection is an increasingly used solution for disposing of toxic waste, but there are lots of problems with it.
Step 4: Evaluate the Answer Choices
(D) is correct, describing the author’s negative view toward deep-well injection.
(A) is a Distortion. This only describes deep-well injection as unsafe in the absence of expensive precautionary measures. However, the author does not discuss such measures or claim that they would make deep-well injection safer.
(B) is Out of Scope. The author focuses exclusively on the problems with deep-well injection, not procedures that would make it safe.
(C) is Extreme. The author claims that deep-well injection is increasingly used, not that it has “wholly supplanted” other methods. Moreover, this choice entirely ignores the author’s scope: the problems with deep-well injection.
(E) is a Distortion. While deleterious effects on drinking water are one problem the author cites for deep-well injection, the passage concentrates on this and other problems, not on the design and location of injection facilities.

2. (C) Inference
Step 1: Identify the Question Type
The question asks for something the passage “strongly suggests,” making this an Inference question.
Step 2: Research the Relevant Text
With no line references or content clues, the correct answer could be supported by a statement from anywhere in the passage. Everything is potentially relevant.
Step 3: Make a Prediction
An open-ended question like this can be impossible to predict. Instead, go through the choices individually, sticking close to the author’s tone and watching out for extreme choices. Use content clues in the choices to do further research, if needed.
Step 4: Evaluate the Answer Choices
(C) is correct. According to the third paragraph, one potential problem with deep-well injection is that various geological factors can lead to waste being transported “thousands of meters per year” underground.
(A) is Out of Scope. In the first paragraph, the author suggests that industries have switched to deep-well injection because regulations make landfills and incinerators expensive, not because those methods are unsafe.
(B) is a 180. According to the first paragraph, drilling doesn’t occur below 1,800 meters because it then becomes less cost-effective, suggesting that it’s more expensive to drill that deep. And the author says nothing about it being any more or less dangerous at deeper levels.
(D) is Out of Scope. The author makes no mention of whether landfills affect groundwater.
(E) is a 180. In the first paragraph, the author mentions that waste wells are usually drilled at a safe distance below aquifers (sources of drinkable water), not above them.

3. (D) Logic Reasoning (Strengthen)
Step 2: Identify the Question Type
The correct answer here will be a fact that, if true, “strengthen[s] the author’s position.” That makes this a Strengthen question much like those found in Logical Reasoning.
Step 3: Research the Relevant Text
The author’s conclusion is that deep-well injection is risky. The evidence is all of the information from the second and third paragraphs: that wells can leak, workers can make mistakes, and waste may act unpredictably underground.
Step 4: Make a Prediction
The correct answer will provide further evidence that any one of these problems can pose a risk.
Step 5: Evaluate the Answer Choices
(D) is correct. In the third paragraph, the author cites the unpredictability of geology as a potential problem. If things are even more unpredictable than believed, that just makes it more likely that problems will occur, making deep-well injection more likely to be risky.
(A) is a 180. If suitable drilling sites are rarely near sources of drinking water (i.e., further away), then that means the wells are less likely to pose a risk.
(B) is irrelevant. Thorough testing—which hasn’t happened—might show the chemicals to be more or less harmful than previously suspected. What’s more, this choice focuses on the effects on nonhuman organisms, while the author’s argument is based on the risks to people.
(C) is irrelevant. This choice suggests yet another risk: spills or accidents in waste transportation. That doesn’t directly strengthen the author’s point that the wells are unsafe, nor does the author tell you how far waste must be transported under alternative disposal techniques (maybe the sites for alternate disposal are even farther away than the deep-well- injection sites).
(E) is a 180. If methods for studying underground water have gotten better, then it could be easier to predict what will happen, which could actually reduce the assumed risk.


4. (E) Detail
Step 2: Identify the Question Type
The question asks for something that “[a]ccording to the passage ... is true.” That makes this a Detail question.
Step 3: Research the Relevant Text
In the first two paragraphs, the water underground in injection wells is said to be “salt water.” However, more substantial information about this water is provided in the third paragraph, when this water is compared to surface water.
Step 4: Make a Prediction
According to the third paragraph, “water in underground rock strata” differs from surface water in that underground water “does not flow entirely under the influence of gravity,” and it “can be transported thousands of meters per year through geologic faults, porous rock, or other geologic formations.”
Step 5: Evaluate the Answer Choices
(E) is correct, as established by the last sentence of the third paragraph. (A) is a 180, at worst. Contamination is described as a problem. There is
no suggestion that water is okay if contamination is low.
(B) is a 180. The first paragraph mentions how waste wells are often drilled at least 300 meters down, into rock layers that are “saturated with salt water.”
(C) is Out of Scope. There is no mention of whether underground water can be used for industrial processes.
(D) is a 180. The first paragraph suggests that underground rock layers are “already saturated with salt water” when the wells are drilled. It does not say that the waste increases the salinity.


5. (C) Inference
Step 2: Identify the Question Type
The question asks for information “based on the passage,” making this an Inference question.
Step 3: Research the Relevant Text
The author describes the purpose of deep-well injection in the first paragraph.
Step 4: Make a Prediction
According to the first paragraph, deep-well injection is one of the “alternative methods of hazardous-waste disposal” that industries are using because of the “increasing production of toxic waste.”
Step 5: Evaluate the Answer Choices
(C) is correct. It’s a hazardous waste disposal method that, as described in the first paragraph, involves injecting that waste into areas “saturated with salt water.”
(A) is Out of Scope. There is no indication that these wells are temporary or short-term solutions.
(B) is a Distortion. Industries are using deep-well injection to “save time and money,” not because other methods are obsolete.
(D) is a 180. In the third paragraph, the author cites the difficulty of predicting what will happen to the wastes as one of the method’s problems. That suggests it cannot be reliably monitored.
(E) is Out of Scope. The author makes no mention of recycling waste.


6. (A) Detail
Step 2: Identify the Question Type
This is a Detail question. The phrase “[a]ccording to the passage” indicates that the correct answer will be directly stated in the passage.
Step 3: Research the Relevant Text
The question asks about what deep-well injection “has become,” so you’re looking for something the author has identified as a recent trend or occurrence. A quick glance at the answer choices reveals that this method has either become “more controversial” or “more widely accepted.” This refers to information in the first paragraph.
Step 4: Make a Prediction
At the end of the first paragraph, the author mentions that deep-well injection has become “a matter of controversy as growing numbers of communities come to rely on underground sources of drinking water.”
Step 5: Evaluate the Answer Choices
(A) is correct, paraphrasing the end of the first paragraph.
(B) is Out of Scope. There is no mention of toxin-related illnesses.
(C) is a Distortion and a 180. At the beginning of the passage, deep-well injection is identified as less expensive than landfills and incinerators. However, those solutions are not “newly developed alternatives.” Besides, deep-well injection has become controversial, not widely accepted.
(D) is partly Out of Scope, and partly a 180. There is no mention of increased public awareness of environmental problems, and deep-well injection has become controversial, not widely accepted.
(E) is a 180. Deep-well injection is controversial. It is not widely accepted, precisely because of how toxic the effects of the waste can be on drinking water.


7. (B) Inference
Step 2: Identify the Question Type
The correct answer will be “based on the passage” and will most accurately describe criteria the author has outlined. That makes this an Inference question.
Step 3: Research the Relevant Text
The question asks about the “ideal characteristics” for a deep-well- injection area. That strongly relates to the phrase “[u]nder the best conditions,” which begins the second paragraph. Those conditions, the passage says, involve injecting waste into rock strata “saturated with salt water” and “separated by impermeable rock strata from aquifers.” You get a little more context from the details in the first paragraph, where the author states that the strata “saturated with salt water” is “porous and permeable.” Also, the minimum depth for waste wells is 300 meters, which is “below any aquifer.”
Step 4: Make a Prediction
So, the ideal conditions would be in porous, permeable, salt-water- saturated rock that is separated by impermeable rock strata from the aquifers above it.
Step 5: Evaluate the Answer Choices
(B) is correct, connecting the information from the first paragraph to the “best conditions” described in the second paragraph.
(A) is a 180. The well should be below aquifers. So, the protective layer of impermeable rock should be above the well, not below it.
(C) is a Distortion. The layer of impermeable rock should separate the well from the aquifer above it. So, it should be below the aquifer and above the well. It need not start at the surface.
(D) is a 180. The waste well should be separated from the aquifer, and it is usually at a depth of 300 meters or more, not less.
(E) is a Distortion. Wells at 1,800 meters are said to be less cost- effective, and they’re not said to be any better than wells at 300 meters.