What characteristic gives the red river its name?
a. the water collects minerals from reddish-orange soils.
b. the river's source is in mexico's rojo mountains; "rojo" is spanish for "red."
c. high acidity in the river turns the water reddish-orange
d. plants growing on the banks drop leaves that stain the water reddish-orange

A. The water collects minerals from reddish-orange soils.

Explanation:

The Red River (also called the Southern Red River) is located in the southern United States and flows southeast through Texas and Oklahoma.

Its name is due to the fact that the river transports large amounts of red soil, coming from the bed of its basin, during flood periods. Another important feature of this river is that it has a high salt content.

the indians crossed artificial boundaries, setting the stage for conflict

the anwser is missions