.Whywasitoncethoughtthatnospacecraftwouldsurviveforverylongin\rspace?\r(A)Peoplebelievedthatspacecraftwouldbedestroyedinablackhole.\r(B)Peoplebelievedthatspacecraftwouldbemisguidedbymissiles.\r(C)Peoplebelievedthatspacecraftwouldbecollidedwithastar.\r(D)Peoplebelievedthatspacecraftwouldbedamagedbymeteorites.\r29.WhatisthegreatestdangertolifeonEarth?\r(A)Collisionwithsmallhigh-speedmissiles.\r(B)Collisionwithanastronomicalbody.\r(C)Collisionwithstonesfromthesky.\r(D)Collisionwithspacecrafts.\r30.Accordingtothepassage,whichofthefollowingstatementsistrue?\r(A)Ourgalaxycontainsgreatinterstellardustclouds.\r(B)Nearmissesofbodiessmallerthanourownplanetcouldbedisastrous.\r(C)Theprobabilityofcollisionwithalargeastronomicalbodyisveryhigh.\r(D)Thechancesofanyoneactuallybeinghitbymissilesareveryhigh.