Bunuel
Some cleaning fluids, synthetic carpets, wall paneling, and other products release toxins, such as formaldehyde and benzene, into the household air supply. This is not a problem in well-ventilated houses, but it is a problem in houses that are so well insulated that they trap toxins as well as heat. Recent tests, however, demonstrate that houseplants remove some household toxins from the air and thereby eliminate their danger. In one test, 20 large plants eliminated formaldehyde from a small, well-insulated house.
Assume that a person who lives in a small, well-insulated house that contains toxin-releasing products places houseplants, such as those tested, in the house.
Which one of the following can be expected as a result?
(A) There will no longer be any need to ventilate the house.
(B) The concentration of toxins in the household air supply will remain the same.
(C) The house will be warm and have a safe air supply.
(D) If there is formaldehyde in the household air supply, its level will decrease.
(E) If formaldehyde and benzene are being released into the household air supply, the quantities released of each will decrease.
OFFICIAL EXPLANATION
This problem asks us to draw a conclusion.
Choice (A) overstates the claim made in the passage. The passage states that “houseplants remove some household toxins from the air,” not all toxins.
Choice (B) contradicts what the passage implies would happen. The concentration of toxins in the household air supply should decrease, not remain the same.
Choice (C), like (A), overstates the claim made in the passage—“houseplants remove some household toxins from the air,” not all toxins.
Choice (D) is a reasonable conclusion to make since the passage states that “houseplants remove some household toxins from the air” and that in one test they even eliminated formaldehyde from a house. Hence the answer is probably (D), but it’s prudent to check the last answer-choice.
Choice (E) is not supported by the passage. Household plants eliminate certain toxins; nothing in the passage suggests that they prevent the toxins from being released.
The answer is (D).