At the heart of a comer's coma lies a nucleus of solid material, typically no more than 10 kilometers across.
6 L; W# |" L+ n( u3 _3 OThe word "heart" is closest in meaning to which of following?
. ~, n& p- m& \(A) center, X7 {1 R9 W0 d7 D. q1 Q
(B) edge V) F( ?% \* k2 W: `
(C) tail
6 N+ E2 r, E4 A% f(D) beginning) p3 ~, J1 j% e
: p1 {% b# v( ?# g$ t The most graphic proof that the grand spectacle of a comet develops from a relatively small and inconspicuous chunk of ice and dust was the close-up image obtained in 1986 by the European Giotto probe of the nucleus of Halley's Comet. ]) c) P o4 F" I, {# C9 M7 ~7 [
The word "graphic" is closest in meaning to which of following?% H- ^4 s0 Q& C$ `0 p
(A) mathematical" d3 z& _ B/ t H8 R( e% u
(B) popular8 y- W( [9 T3 K" A
(C) unusual# R0 l/ M4 n3 k; E. ^
(D) vivid! I% J! J2 N" K
- g K X) P% K" C* v! H
403. As a comet's orbit brings it closer to the Sun, first the coma grows, then two distinct tails usually form.8 U: ]: ?% }4 l
The word "distinct" is closest in meaning to which of following?% z3 c) x3 {% e& }3 X& D4 e
(A) visible/ k+ a) N3 Y; v' q0 D' C% D0 g
(B) gaseous
0 n$ M g d2 t1 n9 H(C) separate
( C+ K: ?; B& X9 [6 f(D) new
( v# j9 g; L, _" O7 f' g( u- I+ x5 J
. Pheromones are substances that serve as chemical signals between members of the same species.1 Q6 l1 F; x2 d2 f
The word "serve" is closest in meaning to which of following?
6 g) b2 v% T- C(A) improve4 c) a' _2 T2 J
(B) function
- K; j# F2 G4 B( W(C) begin5 J8 c, ^& M9 y9 }8 k* Y6 w1 ~. j
(D) rely7 C! b: Z! @4 G0 A
# F1 y! @# Q9 N, k8 a" T: J1 @. Pheromones are the predominant medium of communication among insects (but rarely the sole method) . Some species have simple pheromone systems and produce only a few pheromones, but others produce many with various functions.
+ R. Z n* O( x; ~% ]5 kThe word "sole" is closest in meaning to which of following?
+ v8 G* E( |/ R# `) {(A) obvious
8 Q( g& n7 H; I: `( L; C! }(B) best
1 n' h2 B0 C- ]1 V8 o(C) only* E J: r7 [6 n2 x, J% {! q' ?
(D) final
4 x" f* W. J" \: GADCBC |