Somescientistssaythatanimalsintheoceanareincreasinglythreatenedbynoisepollutioncausedbyhumanbeings.
Thenoisethataffectsseacreaturescomesfromanumberofhu?manactivities.Itiscausedmainlybyindustrialunderwaterexplo?sionsoceandrillingsandshipengines.Suchnoisesareaddedtonaturalsounds..Thesesoundsincludethebreakingoficefieldsunderwaterearthquakesandsoundsmadebyanimalsthemselves.
Decibels(分贝)measuredinwateraredifferentfromthosemeasuredonland.Anoiseofonehundredandtwentydecibelsonlandcausespaintohumanears.Inwateradecibellevelofonehundredandninetyfivewouldhavethesameeffect.
Somescientistshaveproposedsettinganoiselimitofonehundredandtwentydecibelsinoceans.Theyhaveobservedthatnoisesatthatlevelcanfrightenandconfusewhales.
AteamofAmericanandCanadianscientistsdiscoveredthatloudernoisescanseriouslyinjuresomeanimals.
Theresearchteamfoundthatpowerfulunderwaterexplosionswerecausingwhalesintheareatolosetheirhearing.Thisseriouslyaffectedthewhales'abilitytoex?changeinformationandfindtheirways.Someofthewhalesevendied.Theexplo?sionshadcausedtheirearstobleedandbecomeinfected.
Manyresearcherswhoseworkdependsonoceansoundsobjecttoalimitofonehundredandtwentydecibels.Theysaysuchalimitwouldmeananendtoimportantindustrialandscientificresearch.
Scientistsdonotknowhowmuchandwhatkindsofnoisesareharmfultooceananimals.Howevermanyscientistssuspectthatnoiseisagreaterdangerthantheybelieved.Theywanttopreventnoisesfromharmingcreaturesintheocean.
1.Accordingtothepassagewhichofthefollowingisincreasinglydangeroustoseacreatures?
A.Thesoundofacar.B.Thesoundofvoices.
C.Manmadenoisepollution.D.Thesoundofsteps.
2.AccordingtothepassagenaturalsoundsincludeallofthefollowingEXCEPT
A.soundsmadebyanimalsthemselves
B.oceandrillings
C.underwaterearthquakes
D.thebreakingoficefields
3.Whichofthefollowingisdiscussedinthethirdparagraph?
A.Thesa