How can water change the course of a river?

Which of there factors contributed most to us westward expansion in the second half of the nineteenth century?

Click the item in the left column. use the plus sign to move it up or the minus sign to move it down until it matches the correct entry in the right column. lock your answer in place by clicking the square beside the item. (a checkmark means it is locked.) amazon basin a atacama desert b andes mountains c lake titicaca d peru e patagonia f brazil g chile h suriname

Look at the photo i can’t do geography