quEstions 17 to 20 ArE BAsED on thE Following pAssAgE.At thE EnD oF thE pAssAgE, you will BE givEn 20 sEConDs to AnswEr thE quEstions. now, listEn to thE pAssAgE.

whAt hAs hAppEnED sinCE thE EnD oF thE lEEAgEA．mAny spECiEs hAvE movED FurthEr north.
B．mAny nEw spECiEs hAvE ComE into ExistEnCE.
C．mAny spECiEs hAvE DEvElopED A hABit oF migrAtion.
D．mAny spECiEs hAvE BEComE lEss sEnsitivE to ClimAtE.