ELIC 12.2 Purpose Questions

Spiders are often referred to as insects, but they are certainly not insects.

Unlike insects, spiders do not have antennae or wings. They also have eight

simple eyes while insects have two compound eyes. Spiders have eight legs,

whereas insects have six. A few spider species build webs and live in large

colonies. This is a social behavior, although not nearly as complex as the

social relationships found among insects. The species Anelosimus Eximius

forms colonies of up to 50,000 individual spiders. The Theridion

Nigroannulatum spider co-operates to capture prey and share food with each

other. Predatory spiders such as these are in a better position to defend their

meals from parasites that would otherwise steal it. Social behavior allows

spiders to team up and capture larger prey. Spiders that co-operate can also

do well in inclement weather. Spiders that share the task of maintaining and

repairing their webs in the rain fare much better than lone spiders.

Why does the professor mention insects?

• To introduce the idea that spiders only take the form of insects at certain

  life stages

• To argue that all spiders are social

• To point out the similarities between spiders and insects

• To correct a common misunderstanding about spiders

Answer explanation

The correct answer is the fourth answer. The writer is correcting a common

misunderstanding: that spiders are insects. The clue is in the next sentence, “Unlike insects, spiders...” The first answer and second answers both contain incorrect information. The third does not reflect the author’s purpose.

Photosynthesis is a process by which plants use sunlight to make their own

food. Plants convert light energy from the sun into chemical energy that can

be later released to fuel the organisms’ activities. This chemical energy is

stored in carbohydrate molecules, such as sugars, which are synthesized from

carbon dioxide and water. Oxygen is released as a waste product. Cellular

respiration, on the other hand, converts the food created by photosynthesis

into energy which can then be utilized by the living organisms or plants. This

process occurs within the mitochondria, organelles which break down

glucose. All living organisms and plants perform cellular respiration. In

contrast, photosynthesis can only be performed by organisms that contain

chlorophyll, green pigments found in algae and plants.

What is the purpose of this paragraph?

• To give examples of organisms that perform photosynthesis

• To explain how organisms perform cellular respiration

• To define and explain the process of photosynthesis

• To compare photosynthesis and cellular respiration

Answer explanation

The fourth answer is correct. The purpose of the paragraph is to compare photosynthesis

and cellular respiration. Take note of the transitional phrases, “on the other hand” and “in contrast.”

Eating is a much more intense experience in babies than adults. Babies have

over thirty thousand taste buds in their mouths. They are replaced with

healthy new taste buds every two weeks. Over time, however, the body no

longer replaces them and the sense of taste becomes much less discerning. An

adult has 1/3 the number of healthy taste buds as a six-month-old baby.

Babies are wired for a preference for fat and sugar-packed milk. Infants also

need more calories in relation to their body size, and do not tend to enjoy

salty or sour flavors. The reason children often reject vegetables could be that

the bitter notes in them are magnified by the high number of functioning taste

buds. In addition, parental nagging to “eat your vegetables” may cause a

negative association with vegetables and a desire to rebel against the parent’s

demands. As a person matures, they express entirely different preferences.

Adults may develop a liking for sharp, pungent, or bitter tastes such as blue

cheese, garlic, and brussels sprouts.

The author mentions blue cheese, garlic, and brussels sprouts in order to:

• give examples of foods that children refuse to eat

• indicate foods that offer health benefits

• provide examples of foods that adults enjoy more than children

• compare the tastes of three different types of foods

Answer explanation

“Develop a liking” means “begin to enjoy.” The author is giving examples of foods that adults enjoy more than children. The clue is the words “such as.” Why are the others incorrect? The first answer has the correct purpose, but uses extreme language (“refuse to eat.”) The second is off-topic. The fourth does not reflect the author’s purpose.

For a fossil to be discovered, a series of steps must occur. The animal or plant

must be buried quickly. If it dies on the plains or in a rocky area, it is usually

found by scavengers, eaten and reduced to bone chips. Animals that do get

fossilized are those which get caught in floods, die in or near a river, or get

trapped in a sandstorm. The dead animal then must be buried in a

depositional area and covered in layers of mud and sediment. Dissolved

minerals, transported by groundwater in the sediment, fill tiny spaces in the

bones. The combination of pressure and chemical reactions eventually turn

the sediments into rock and the bones into mineralized fossils. Next, the

depositional area must become an erosional area so that wind and water wear

it down to uncover the fossil remains. Finally, someone knowledgeable must

spot the fossil and recover it. It must be a short time from the fossil becoming

exposed to recovery by an expert. If it isn’t recovered quickly, erosion will

eventually wear away the fossil itself.

What is the purpose of this paragraph?

• To give information about the methods scientists use to recover fossils

• To explain the steps in a process

• To demonstrate the difficulties in recovering fossils

• To argue that most fossils disappear before they are discovered

Answer explanation

The second answer seems a

lot less appealing than the other answers. Remember from earlier in this book: Sometimes a simple answer is correct. Look at the big picture, especially the first sentence. It says “...a

series of steps must occur.” The paragraph also has words that indicate steps, such as next and finally. None of the other answers are related to the big picture.

Soil contamination occurs when human activity introduces chemicals into the

soil that damage living organisms. Plants called hyperaccumulators are

incredibly useful because they can absorb pollutants from the ground without

being poisoned themselves. The evolutionary advantage of the

hyperaccumulation of metals by plants may be that the toxic levels of heavy

metals deter herbivores from consuming them. These useful plants can

provide a natural and inexpensive way to clean up after an accident and help

to regain soil stability. Hyperaccumulators can absorb contaminants in either

soil or groundwater; whether it is heavy metals, chemicals, radioactive

contamination or petroleum. For example, sunflowers were used to absorb

radioactive contamination after the Chernobyl disaster in the Ukraine.

Wildflowers were used in Kuwait to clean up sites where petroleum had

spilled. Even showy, beautiful flowers can be hyperaccumulators. Gerbera

Daisies are flowers with large pink petals that can absorb formaldehyde from

the soil.

Why does the professor mention Gerbera Daisies?

• To give an example of a showy, beautiful flower

• To show that hyperaccumulators can absorb radioactive waste

• To warn about the risks of growing these daisies

• To point out one way soil contamination can be reduced

Answer explanation

The first is off topic. The passage is about

hyperaccumulators, not showy flowers. The second answer is a trap: it uses some of the same language, but sunflowers were used to absorb radioactive waste, not Gerbera Daisies. The third answer has the wrong tone. It uses the word “risks,” a negative word. The author

has a positive tone, praising the uses of hyperaccumulators.

You may have heard the expression, “as blind as a bat.” But are bats really

blind? Because bats use echolocation, sonar-like systems to detect and locate

objects by emitting high-pitched sounds, many people assume bats are blind.

In fact, all 1,100 species of bats are able to see, although their vision is not as

acute as other nocturnal animals. Two main groups of bats have evolved

independently of one another. One group, the Megachiroptera, are medium-

sized bats with complex visual centers in their brains and large eyes to spot

prey. The Flying Fox bat, for instance, is able to see very well and in a full

range of colors. The second group, Microchiroptera, is smaller with tiny eyes.

Although the visual center in their brains is not as complex as the

Megachiroptera, they have photoreceptor cells in the retinas of their eyes;

cones for use in the daylight and to detect color, and rods which they use for

low light conditions in the evening and during the night. They use their vision

to see over long distances, beyond the range in which echolocation would

function. The False Vampire Bat, for instance, has been observed catching

prey in the dark without using echolocation.

The author asks the question “But are bats really blind?” for which of the following reasons?

• To introduce a discussion of bat vision

• To ask why bats are unable to see very well

• To cast doubt on a bat’s ability to use echolocation

• To compare the vision of two groups of bats

Answer explanation

Don’t forget to look at the big picture of the paragraph, which is a discussion of bat vision.

Therefore, the first answer is correct. The question is used to introduce the topic of bat

vision.

Dinosaurs ruled the planet from 230 million to 65 million years ago, at which

time they suddenly went extinct. This marked the end of the Mesozoic era.

But why did these formidable creatures disappear? Many hypotheses have

been examined, including climate change. Evidence does show that the planet

had become much cooler. There was ice at the poles, and the temperatures of

the ocean dropped. If that theory is correct, however, how can the survival of

alligators and turtles be explained? Like the dinosaurs, these animals are

ectotherms that rely on external temperatures to maintain a survivable

internal body temperature. If these ectotherms were able to survive the same

climate change, it stands to reason dinosaurs would have been able to as well.

In addition, climate change takes tens of thousands of years to occur, which

would have given dinosaurs time to adapt. While the climate change

hypothesis is tempting, evidence shows that it is insufficient in explaining

this extinction event.

Why does the author mention alligators and turtles?

• To point out that ectotherms can survive changes in temperature

• To cast doubt on the theory that dinosaurs died due to climate changes

• To argue that dinosaurs went extinct because they were not ectotherms

• To give examples of animals that survived the end of the Mesozoic era

Although they may appear as tough as rock at first glance, coral reefs are

very delicate ecosystems which are easily damaged or destroyed. Careless

fishing methods, oil spills, land runoffs, and even the sunscreen worn by

swimmers can cause death to this ecosystem. The destruction of coral reefs is

a serious issue because these reefs provide a vital food source for 500 million

people who live near the coasts. They generate billions of dollars in revenue

for communities; in fact, it is estimated that their value in tourist dollars is

$30 billion a year. In addition, coral acts as a natural barrier from weather

events such as hurricanes and typhoons. Coral reefs, much like the rainforest,

may contain compounds which could be used to treat disease. Even much of

the air that we breathe comes from coral reefs. The decline of this valuable

and fragile ecosystem could be disastrous for humanity.

What is the author's purpose in providing examples of how coral reefs can be

killed?

• To emphasize how fragile this ecosystem is

• To give examples of how to protect the coral reefs

• To explain why coral reefs should be protected

• To point out that coral reefs are more delicate than the rainforest

Answer explanation

The author is emphasizing the main point: that this is a very

fragile (delicate) ecosystem. The second answer is off topic. The third answer has the

wrong purpose. The fourth answer is a trap: it uses some of the words from the passage in a misleading way.