La#Crise#KT.#
Le#Sujet#de#L’article#:#La#Crise#KT.##
!
"#!$%&'(!)%*+#$*,-(%+&#&%(!('+!./01(!2('!$&13!$%&'('!4#5(0%('!30&!61+!4#%30*!.('!+(47'!
78#1*%696:30(';!'6&+!.('!<=<!2(%1&(%'!4&..&61'!2/#11*('!2(!./8&'+6&%(!2(!.#!>&(!'0%!-(%%(?!)(++(!$%&'(!@!
.(!+&+%(!2(!$%&'(!.#!7.0'!A6%+(!5#4#&'!(1%(B&'+%*(;!$/('+!.#!$%&'(!.#!7.0'!$*.CD%(;!(..(!%(7%*'(1+(!.#!
2&'7#%&+&61!2('!2&16'#0%('!#&1'&!30(!2(!164D%(0'('!#0+%('!
$#+*B6%&('!2/6%B#1&'4('!30&!61+!*+*!+60$8*'?!)/('+!B%E$(!@!$(++(!
$%&'(!30(!.('!4#44&AC%('!1(!'(%61+!7.0'!264&1*'!(+!30/&.'!'(!
2&>(%'&A&(%61+?!"#!.&4&+(!(1+%(!.#!A&1!20!)%*+#$*!(+!.(!2*D0+!2(!./C%(!
-(%+&#&%(!('+!4#%30*(!'0%!.(!+(%%#&1!7#%!.#!7%*'(1$(!2/01(!A&1(!
$60$8(!2/#%B&.(!16&%(!(1+%(!.('!2(0F!'+%#+('!B*6.6B&30('?!G0%!.#!
'+%#+(!$6%%('7612#1+!#0!2*D0+!20!+(%+&#&%(;!.#!+6+#.&+*!2('!
#4461&+('!H&4#B(!@!2%6&+(I!2&'7#%#&''(1+?!G0%!$(++(!4J4(!'+#+(;!
$61+&1(1+#.(!$(++(!A6&'!$&;!$/('+!./(1'(4D.(!2('!2&16'#0%('!30&!
2&'7#%#K+!#0!7%6A&.!2('!4#44&AC%('?!
Les#causes#de#cette#crise#biologique#
!
L.!M!#!2(0F!8M76+8C'('!30&!760%%#&+!(F7.&30(%!.#!462&A&$#+&61!%#7&2(!2(!./(1>&%611(4(1+!@!./6%&B&1(!2(!
$(++(!$%&'(!D&6.6B&30(!N!
O? P1!>6.$#1&'4(!&1+(1'(!
)/*+#&+!&.!M!#!Q<!4&..&61'!2/#11*(';!(1!L12(!2#1'!.(!R($$#1;!01(!*%07+&61!>6.$#1&30(!#0%#&+!(0!.&(0?!
)(++(!2(%1&C%(!#0%#&+!*+*!$#0'*(!7#%!01!76&1+!$8#02!30&!('+!#0560%2/80&!'&+0*!@!.#!S*01&61?!HP1!76&1+!
$8#02!7(0+!7(%$(%!.#!.&+86'78C%(!(+!.#!$%6T+(!+(%%('+%(!(+!&.!('+!$#0'*!7#%!2('!7#1#$8('!2(!4#+*%&#0F!
$8#02'!30&!%(461+(1+!20!4#1+(#0!7%6A612I?!L.!'/#B&%#&+!2/01!>6.$#1&'4(!2(!76&1+!$8#02!30&!'(!'(%#&+!
2*$.#%*!(1!961(!$61+&1(1+#.(?!G('!*%07+&61'!'61+!261$!(F7.6'&>('!(+!+%C'!7%620$+&>('?!L.!M!#!2/*16%4('!
30#1+&+*'!2(!B#9!!H)UV!(+!GUVI!(+!2('!760''&C%('!>6.$#1&30('!2#1'!./#+46'78C%(!7(12#1+!2('!
$(1+#&1('!2(!4&..&(%'!2/#11*('?!)(++(!20%*(!.61B0(!'/#$$6%2(!#>($!.('!2&'7#%&+&61'!7.0'!.(1+('!2(!
$(%+#&1('!('7C$('?!!!
V? P1!&47#$+(!2(!4*+*6%&+(!
R#1'!01(!A&1(!$60$8(!2/#%B&.(!'*7#%#1+!.(!)%*+#$*!20!
-(%+&#&%(;!2(!./&%&2&04!(=#métal#très#rare#sur#Terre#mais#
présent#en#grande#quantité#dans#les#astéroïdesI!(1!
30#1+&+*!#16%4#.(!#!*+*!2*$60>(%+?!P1(!2*$60>(%+(!#!
%(1A6%$*(!./8M76+8C'(!2(!.#!4*+*6%&+(;!$/('+!$(..(!20!
$%#+C%(!2(!)8&$F0.0D;!VWW!X4!2(!2&#4C+%(;!2#1'!./K.(!
20!Y0$#+#1?!L.!'(!'(%#&+!A6%4*!&.!M!#!,Q<!4&..&61'!2/#11*('!'0&+(!@!.#!$80+(!2/01!#'+*%6:2(!2(!OW!X4!2(!
2&#4C+%(?!)(.#;!@!.#!'0%A#$(!20!B.6D(;!7(0+!#>6&%!2('!(AA(+'!2*>#'+#+(0%'!'0%!.#!D&6'78C%(?!L.!M!#!+60+!
2/#D6%2!./612(!20!$86$!(+!.('!&1$(12&('!30&!'61+!20'!@!.#!B%#12(!.&D*%#+&61!2/*1(%B&(!4#&'!&.!M!#!
*B#.(4(1+;!.#!2&AA0'&61!2(!7#%+&$0.('!2#1'!./#+46'78C%(?!G/&.!M!#!01!&47#$+!'0%!.('!$61+&1(1+';!.('!
760''&C%('!&15($+*('!2#1'!./#+46'78C%(!!D.630(1+!.('!%#M61'!20!'6.(&.!7(12#1+!7.0'&(0%'!46&';!$(!30&!
2611(!.&(0!@!01!Z!8&>(%!2/&47#$+![?!G/&.!M!#!01!&47#$+!2#1'!.('!6$*#1';!.('!B60++(.(++('!2/(#0!30&!'61+!
7%670.'*('!2#1'!./#+46'78C%(!7%6>630(1+!01!Z!8&>(%!2/&47#$+![!70&'!%*$8#0AA(1+!.#!7.#1C+(!(1!
%(1A6%\#1+!./(AA(+!2(!'(%%(?!]0&'30/&.!1/M!#!7#'!2/*1(%B&(!'6.#&%(;!$/('+!.#!A&1!2(!.#!786+6'M1+8C'(!261$!
$/('+!./(AA612%(4(1+!2('!$8#K1('!#.&4(1+#&%(';!.('!7.#1+(';!.('!8(%D&>6%(';!.('!$#%1&>6%('?!
!
]60%!.(!O^?W_?VWO_!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!](%6+!)8.6*!_`_!
1 / 2 100%
La catégorie de ce document est-elle correcte?
Merci pour votre participation!

Faire une suggestion

Avez-vous trouvé des erreurs dans linterface ou les textes ? Ou savez-vous comment améliorer linterface utilisateur de StudyLib ? Nhésitez pas à envoyer vos suggestions. Cest très important pour nous !