PrepTest 114, Section 4, Question 3
Journalist: Obviously, though some animals are purely carnivorous,(65 more words not shown)
Which one of the following(10 more words not shown)
- AThe photosynthetic activity(20 more words not shown)
- BSome purely carnivorous(6 more words not shown)
- CThe chemical composition(22 more words not shown)
- DHuman activity is(19 more words not shown)
- EJust as animals(14 more words not shown)
Reading the argument
A lion can depend on plants without eating them. Picture a lion eating a gazelle that feeds on plants: the lion depends on the plants indirectly, through its food. That helps me follow the journalist's opening point about even purely carnivorous animals.
Then the journalist says the dependence goes both ways. How do plants need animals? My first thought is that predators might keep plant-eating populations in check. But that isn't the explanation the journalist gives. Instead, animals help plants reproduce by pollinating, fertilizing and spreading seeds. The passage also describes animals and human activities replenishing carbon dioxide that plants use.
What we’re looking for
Now the question asks for the main conclusion. The details about reproduction and carbon dioxide explain the second side of the relationship: plants depend on animals too. So I'd look for the broad claim of mutual dependence. The examples support that point; they aren't separate conclusions we need to substitute for it.
Working the answers
- A
This changes the broad claim about survival into a claim about the occurrence of photosynthesis. The carbon dioxide discussion helps explain how plants depend on animals, but the argument also relies on pollination, fertilization and seed dispersal. A doesn't capture that full point. Nor does the passage establish that no photosynthesis could occur at all without animal life; the stated concern is depletion without continuing replenishment.
- B
This concerns the opening side of the relationship: carnivores need plants. It is compatible with the stronger statement that none of them could survive without plants. The problem isn't that 'some' contradicts 'all.' The problem is that B stops at the background point and omits the journalist's main addition that plants also depend on animals.
- C
Animal activity affecting atmospheric composition is part of the explanation. The passage mentions replenishing carbon dioxide to show why plants need animals. C shifts the focus to chemical composition rather than stating the claim about mutual dependence for survival.
- D
This names the wrong gas. The passage says photosynthetic activity would deplete carbon dioxide, not oxygen. It also narrows the discussion to human activity when the argument concerns animals more broadly. Even a corrected statement about humans replenishing carbon dioxide would capture only part of the support, not the main conclusion.
- ECorrect
This states the relationship in both directions: animals depend on plants, and plants depend on animals. The opening gives us the first direction; the journalist then asserts that the dependence is mutual and supports the other direction with the reproduction and carbon dioxide examples. E gathers those pieces into the point they are meant to establish.
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