Leaf beetles damage willow trees by stripping away their leaves, but a combination of parasites and predators generally keeps populations of these beetles in check. Researchers have found that severe air pollution results in reduced predator populations. The parasites, by contrast, are not adversely affected by pollution; nevertheless, the researchers\u2019 discovery probably does explain why leaf beetles cause particularly severe damage to willows in areas with severe air pollution, since ________.<\/p>\n
(A) neither the predators nor the parasites of leaf beetles themselves attack willow trees<\/p>\n
(B) the parasites that attack leaf beetles actually tend to be more prevalent in areas with severe air pollution than they are elsewhere<\/p>\n
(C) the damage caused by leaf beetles is usually not enough to kill a willow tree outright<\/p>\n
(D) where air pollution is not especially severe, predators have much more impact on leaf-beetle populations than parasites do<\/p>\n
(E) willows often grow in areas where air pollution is especially severe<\/p>\n
Question Discussion & Explanation<\/a><\/p>\n Correct Answer<\/strong>\u00a0- D<\/span>\u00a0-\u00a0(click and drag your mouse to see the answer)<\/p>\n If (1) (2)
\nQuant<\/h2>\n
and
are negative integers, then what is the value of
?<\/p>\n
<\/p>\n
<\/p>\n