Answer:
In the mid-1800s pioneers who travel through the great plains to the west faced
Step-by-step explanation:
The main cause of death along the way was the disease, such as dysentery and cholera, common in migrants, and which killed many along the way.
Most of the pioneers began their trip in San Luis. It was a hard and full of mishaps, such as rain, dust and wind, although finally they used to have problems also in the mountain sections.
The answer is: Summer rain storms and steep mountains.