Hundreds of seals have died recently from consuming fish of a certain- G: A* a8 T/ C* @* W9 C
species that have been contaminated with an industrial chemical that is, x7 D" d$ X9 f- W
toxic to mammals, even in small amounts. Yet even though many people
' {) Y6 ~- j' ]4 p8 t salso eat fish of that species, none of these people have been harmed8 |9 f7 G: Y, g" L6 m2 x
as a result.6 s3 N- K6 }$ C5 Z* c" p, d; H
Which of the following, if true, most helps to resolve the apparent6 m5 k/ }- I1 F0 o2 u
discrepancy?1 L# S- P$ e0 d- k- \8 a# z1 B. ~% b
The species of fish contaminated by the toxic chemical is not itself
& P4 }) }$ k" P& s, v harmed by that chemical.
! a( ~# c1 j E The toxic chemical collects in those parts of the fish eaten by seals1 x# a6 n) P0 e
but not by people.
6 ~% i4 p0 j$ S n/ ^ Traces of the toxic chemical have been found in some people
: T: \) b% z0 E, J. l+ D' T+ x whose diets include no fish or fish products.
$ j' p- o* A* J1 ^& K/ R- L0 T The species of fish contaminated by the toxic chemical comprises7 t3 T! x. z' v2 P$ z
a relatively small pa r t of the seals' total diet. ) c" ?, v$ J$ N# }3 K- O! Y# I5 |# V
The toxic chemical remains toxic even after exposure to tempera-
4 C& D3 ~0 ]4 N3 b1 Y3 n tures higher than those at which the fish is generally cooked.
: n' X9 Z3 E/ l' P7 N+ _答案B |
发表于 2012-8-15 12:40:43
