在线等！高分求解

Do you believe some fish have the __36___ to change their sex? Researchers have found 14 kinds of fish that can change from female to male and 8 kinds of fish can change from male to female.
Scientists ___37__ one kind of fish discovered that when the only ___38__ in a group dies or disappears, the largest female changes into a male ___39___ 10 days. Dr Douglas Shapiro has found one kind of fish in the Philippines changes ___40__ to keep the same number of males ___41__females. Studies of 48 groups of this kind of fish __42__ that when males were removed from the group, an equal ____43__ of females changed to males.
Dr Robert R Warner studied a fish called the blue-head wrasse（窿头鱼）. He found the number of sex changes ___44___ on the size of the living area and the __45____ of fish in the group. In small areas ___46__ fewer than 200 fish, large males ___47___ the mating（交配）. The other fish in such a small area are females or become females ___48__ they have no other way to reproduce. The big male ones in a large living area are not able to stop a great number of smaller males __49___ the area to mate with females. Scientists have found that when male fish are able to __50__ freely, they do not change sex. For example, small parrot fish live among sea grass. ___51__ the sea grass, large males cannot see the other males invading the ___52__. The other males are able to mate with the females and no sex change takes__53___.
Researchers believe that the __54___ the fish developed the ability to change sex is to increase __55___.
36. A. ability B. time C. chance D. interest
37. A. bringing B. keeping C. seeing D. studying
38. A. female B. male C. one D. fish
39. A. before B. within C. for D. about
40. A. direction B. order C. sex D. colour
41. A. by B. for C. on D. to
42. A. showed B. told C. explained D. found
43. A. number B. figure C. amount D. quantity
44. A. got B. took C. depended D. put
45. A. speed B. character C. number D. size
46. A. with B. and C. of D. for
47. A. liked B. controlled C. hated D. refused
48. A. so B. if C. though D. because
49. A. exploring B. invading C. visiting D. spying
50. A. go B. mate C. eat D. move
51. A. In the form of B. Except C. Because D. Among
52. A. area B. sea C. homes D. field
53. A. place B. the place C. charge D. up
54. A. idea B. fact C. possibility D. reason
55. A. number B. reproduction C. fish D. males
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