Why did the coahuiltecan live in leantus

The Coahuiltecan were various small, autonomous bands of Native Americans who inhabited the Rio Grande valley in what is now southern Texas and northeastern Mexico. The various Coahuiltecan groups were hunter-gatherers. First encountered by Europeans in the sixteenth century, their population declined due to imported European diseases, slavery, and numerous small-scale wars fought against the Spanish, criollo, Apache, and other Coahuiltecan groups. The survivors were absorbed into the Hispanic and mestizo population of southern Texas or northern Mexico.

In 1886, ethnologist Albert Gatschet found the last known survivors of Coahuiltecan bands: 25 Comecrudo, 1 Cotoname, and 2 Pakawa. They were living near Reynosa, Mexico.[1]

i believe it d) heterogeneous

wait history, who want to talk about history, boring.