题目内容：
回答题：ASpecialClock
Everylivingthinghaswhatscientistscallabiologicalclockthatcontrolsbehavior.Thebiologicalclock________（51）plantswhentoformflowersandwhentheflowersshouldopen.Ittellsinsectswhento__________（52）theprotectivecocoon（防护卵袋）andflyaway,andittellsanimalsandhumanbeingswhentoeat,sleepandwake.
Eventsoutsidetheplantandanimal__________（53）theactionsofsomebiologicalclocks.Scientistsrecentlyfound,forexample,thatatinyanimalchangesthecolorofitsfurbecauseofthe__________（54）ofhoursofdaylight.Intheshort_________（55）ofwinter,itsfurbecomeswhite.Thefurbecomesgraybrownin_________（56）inthelongerhoursofdaylightinsummer.
Innersignalscontrolother_________（57）clocks.Germanscientistsfoundthatsomekindofinternalclockseemstoorderbirdstobegintheirlongmigration_________（58）twiceeachyear.Birds_________（59）fromflyingbecomerestlesswhenitistimeforthetrip,_________（60）theybecomecalmagainwhenthetimeoftheflighthasended.
Scientistssaytheyarebeginningtolearnwhich_________（61）ofthebraincontainbiologicalclocks.AnAmericanresearcher,MartinMoorhead,saidasmallgroupofcellsnearthefrontofthebrain__________（62）tocontrolthetimingofsomeofouractions.These__________（63）tellapersonwhentowake,whento_________（64）andwhentoseekfood.Scientistssaythereprobablyareotherbiologicalclockcellsthat__________（65）otherbodyactivities. A．says
B．asks
C．talks
D．tells
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