why was settlement of the great planis slow to come with settlers passing it by for Calornia and the west coast

The correct answer to this open question is the following.

The settlement of the great plains was slow to come with settlers passing it by for California and the west coast because the plains -although offer great portions of land- it had not the kind of good soil to grow crops, the weather was dry, water was scarce, and in general, terms was not the best place or attractive place to settle in.

Many people accepted to move to the great plains after the passage of the Homestead Act of 1862, which gave the settlers 160-acres to people who accepted live there for five years in a row and worked the land. Another important reason was the construction of the Transcontinental Railroad that improved the transportation of people and goods to the west.

a is correct

hope this let me know if it is right

2686-2181 bce-- "egyptian civilization developed along the nile river in large part because the river’s annual flooding ensured reliable, rich soil for growing crops."

1069-664 bce-- "ancient egyptians developed wide-reaching trade networks along the nile, in the red sea, and in the near east."