Hundreds of seals have died recently from consuming fish of a certain7 ]! o8 T1 A, {6 ^4 x% s" B
species that have been contaminated with an industrial chemical that is
* t( {; B. ?: x/ V! v% [toxic to mammals, even in small amounts. Yet even though many people! g$ G& q- V$ i4 |; m7 I. P
also eat fish of that species, none of these people have been harmed
- M \0 T ^6 n. j- R6 mas a result.5 I$ k+ O, i3 ~/ L$ ]* ^" ]; ]/ `
Which of the following, if true, most helps to resolve the apparent& n/ X% F& X; E5 c1 M' A, c
discrepancy?; W( I V) Q g/ h# e; ]
The species of fish contaminated by the toxic chemical is not itself
9 p: z. d. q( a- f5 I( ? harmed by that chemical.
, o0 I) Z" i$ a The toxic chemical collects in those parts of the fish eaten by seals5 L' F3 \- {# G& ~0 T" B
but not by people.
( O4 Z/ X* U K/ r6 {$ @# m) I Traces of the toxic chemical have been found in some people- C! l8 Z+ R& `" c$ {* N p( F
whose diets include no fish or fish products.
, X' F, W+ V. D/ R# w9 t8 _2 Z The species of fish contaminated by the toxic chemical comprises6 F+ ?4 ]8 H5 t
a relatively small pa r t of the seals' total diet.
7 h) }8 D6 L0 e4 z5 d The toxic chemical remains toxic even after exposure to tempera-
0 L/ ~6 w5 v. C8 B9 x tures higher than those at which the fish is generally cooked.
# H! \- v3 E: k. X答案B |
发表于 2012-8-15 12:40:43
