Text 3In the early 1960s Wilt Chamberlain was one of only three players in the National Ba

Text3

Intheearly1960sWiltChamberlainwasoneofonlythreeplayersintheNationalBasketballAssociation(NBA)listedatoversevenfeet.Ifhehadplayedlastseason,however,hewouldhavebeenoneof42.Thebodiesplayingmajorprofessionalsportshavechangeddramaticallyovertheyears,andmanagershavebeenmorethanwillingtoadjustteamuniformstofitthegrowingnumbersofbigger,longerframes.

Thetr endinsports,though,maybeobscuringanunrecognizedreality:Americanshavegenerallystoppedgrowing.Thoughtypicallyabouttwoinchestallernowthan140yearsago,today’speople–especiallythoseborntofamilieswhohavelivedintheU.S.formanygenerations–apparentlyreachedtheirlimitintheearly1960s.Andtheyaren’tlikelytogetanytaller.“Inthegeneralpopulationtoday,atthisgenetic,environmentallevel,we’veprettymuchgoneasfaraswecango,”saysanthropologistWilliamCameronChumleaofWrightStateUniversity.InthecaseofNBAplayers,theirincreaseinheightappearstoresultfromtheincreasinglycommonpracticeofrecruitingplayersfromallovertheworld.

Growth,whichrarelycontinuesbeyondtheageof20,demandscaloriesandnutr ients–notably,protein–tofeedexpandingtissues.Atthestartofthe20thcentury,under-nutr itionandchildhoodinfectionsgotintheway.Butasdietandhealthimproved,childrenandadolescentshave,onaverage,increasedinheightbyaboutaninchandahalfevery20years,apatternknownastheseculartr endinheight.YetaccordingtotheCentersforDiseaseContr olandPrevention,averageheight–5′9″formen,5′4″forwomen–hasn’tr eallychangedsince1960.

Geneticallyspeaking,thereareadvantagestoavoidingsubstantialheight.Duringchildbirth,largerbabieshavemoredifficultypassingthroughthebirthcanal.Moreover,eventhoughhumanshavebeenuprightformillionsofyears,ourfeetandbackcontinuetostr ugglewithbipedalpostureandcannoteasilywithstandrepeatedstr ainimposedbyoversizelimbs.“Therearesomerealconstr aintsthataresetbythegeneticarchitectureoftheindividualorganism,”saysanthropologistWilliamLeonardofNorthwesternUniversity.

Geneticmaximumscanchange,butd on’texpectthistohappensoon.ClaireC.Gordon,senioranthropologistattheArmyResearchCenterinNatick,Mass.,ensuresthat90percentoftheuniformsandworkstationsfitr ecruitswithoutalteration.Shesaysthat,unlikethoseforbasketball,thelengthofmilitaryuniformshasnotchangedforsometime.Andifyouneedtopredicthumanheightinthenearfuturetodesignapieceofequipment,Gordonsaysthatbyandlarge,“youcouldusetoday’sdataandfeelfairlyconfident.”

31.WiltChamberlainiscitedasanexampleto

[A]illustr atethechangeofheightofNBAplayers.

[B]showthepopularityofNBAplayersintheU.S..

[C]comparedifferentgenerationsofNBAplayers.

[D]assesstheachievementsoffamousNBAplayers.