<prompt> Kulinganiswa kuphi inani lezitshalo ezinomswakama ehlathini elidala? Njengoba kunikezwe umbuzo odlule, bhala umongo onempendulo yawo. Kungaba imisho engu-1 kuya kwengu-20. Umongo:  <response>: Kunobufakazi bokuthi kuye kwaba nezinguquko ezinkulu ezimileni zasehlathini lemvula lase-Amazon eminyakeni engu-21 000 edlule ngenxa ye-Last Glacial Maximum LGM nokwehla kweqhwa okwalandela. Ukuhlaziywa kwemithombo ye-sediment evela kuma-paleolakes ase-Amazon nase-Amazon Fan kubonisa ukuthi imvula eyayikhona emgodini ngesikhathi se-LGM yayincane kunaleyo ekhona manje, futhi lokhu cishe ngokuqinisekile kwakuhlobene nokunciphisa ukumbozwa kwezitshalo ezishisayo ezishisayo emgodini. Nokho, kunempikiswano ngokuthi lokhu kuncishiswa kwakukhulu kangakanani. Abanye ososayensi bathi leli hlathi lemvula lancipha laba izindawo ezincane ezihlukaniswe ihlathi elivulekile namadlelo; abanye ososayensi bathi leli hlathi lemvula lahlala lingashintshile kodwa lalingakaze lifinyelele kude enyakatho, eningizimu, nasempumalanga njengoba kubonakala namuhla. Le mpikiswano iye yaba nzima ukuyixazulula ngoba ukulinganiselwa kokusebenza ehlathini lemvula kusho ukuthi ukuthathwa kwesampula kwedatha kuqondiswa kude nendawo emaphakathi yamanzi ase-Amazon, futhi zombili lezi zincazelo zisekelwa kahle idatha etholakalayo. 