If rat tailed maggots and great beetle were wiped out then they would be two much of the predators and prey then the whole population would be wiped out completely and the food chain would be destroyed if there were all wiped out.
Streams erode sediment from their banks. They pick up and transport sediments. As a stream erodes its banks, it creates a V-shaped valley (Figure above). This contrasts with the U-shaped valleys created by glaciers.
A. Hawaii is known for its numerous hotspots formed one after the other
I would venture to say that the country in South America that has the least amount of disposable water would be probably in northern Chile which is a desert ie the Atacama desert which stretches from the Pacific across to the Andes Mts while on the other hand, in southern Chile there is a temperate climate with significant rainfall and considerable disposable water.
Try using demos graphs to see it. there ed is an app and a website