How was the lewis and clark expedition able to get horses for crossing the mountains from the shoshones?

Lewis and Clark could cross the mountains been helped by the Shoshones' Indians. These Indians had no knives or hatchets, all their wood was split with a wedge of elkhorn and a mallet of stone, their guns were really antiquated. the captains took advantage of this and decided interchange their knives and guns for the Shoshones' best horses.

Once the interchanged was performed. They pointed out an old man that knew the rivers and the mountains, to be the guide.

The horses were brought, and with forty horses and three colts, the captains Lewis and Clark and their devoted followers struggled on to cross the mountain.

d. it adversely affected american productivity

the fact that could also be added to column b is that during world war ii, specifically between the years 1941 and 1945, japan expanded its territory towards the indonesian territory in what was known later as part of the "pacific war". in that time, japan could conquer the philipines, singapore,   borneo, central java, malang, cebu, sumatra and various other islands of the area, therefore expanding its territory for a brief period of time.