阅读下面短文，从每题所给的四个选项中选出最佳答案.Fishhaveears.Really.They'requitesmallandhavenoopeningtotheoutsideworldcarryingsoundthroughthebody.ForthepastsevenyearsSimonT

　　阅读下面短文，从每题所给的四个选项中选出最佳答案.

　　Fishhaveears.Really.They'requitesmallandhavenoopeningtotheoutsideworldcarryingsoundthroughthebody.ForthepastsevenyearsSimonThorroldauniversityprofessorhasbeenexaminingfishearssmallroundearbonescalledotoliths.

　　Asfishgrowsodotheirotoliths.Eachdaytheirotolithsgainaringofcalciumcarbonate（碳酸钙）.Bylookingthroughamicroscope（显微镜）andcountingtheseringsThorroldcandeterminetheexactageofayoungfish.Asafishgetsolderitsotolithsnolongergetdallyrings.Insteadtheygetyearlyringswhichcanalsobecountedgivinginformationaboutthefish'sagejustlikethegrowthringsofatree.

　　Ringcountingisnothingnewtofishscientists.ButThorroldhasturnedtoanewdirection.They'reexaminingthechemicalelements（元素）ofeachotolithring.

　　Thedailyringgivesusthetimebutchemistrytellsusabouttheenvironmentinwhichthefishswamonanygivenday.Theseelementstellusaboutthechemistryofthewaterthatthefishwasin.Italsosayssomethingaboutwatertemperaturewhichdetermineshowmuchoftheseelementswillgatherwithineachotolithring.

　　Thorroldcantellforexampleifafishspenttimeintheopenoceanbeforeenteringthelesssaltywaterofcoastalareas.Hecanbasicallytellwherefisharespendingtheirtimeatanygivenstageofhistory.

　　InthecaseoftheAtlanticcroakerapopularsaltwaterfoodfishThorroldandhisassistanthavesuccessfullyfollowedthetravellingofyoungfishfrommid-oceantothecoastajourneyofmanyhundredsofmiles.

　　Thisisimportanttomanagersinthefishindustrywhoknownearlynothingaboutthewhereaboutsoftheyoungfishformostfoodfishintheocean.EagertolearnabouthistechnologyfishscientistsarenowlendingThorroldtheirears.

　　（1）Whatcanwelearnaboutfishearsfromthetext?

　　[]

　　A.Theyaresmallsoftrings.

　　B.Theyarenotseenfromtheoutside

　　C.Theyareopeningsonlyonfoodfish.

　　D.Theyarenotusedtoreceivesound.

　　（2）Whydoesthewritercomparethefishtotrees?

　　[]

　　A.Treesgainagrowthringeachday.

　　B.Treesalsohaveotoliths.

　　C.Theirgrowthringsare