Which innovation had the greatest impact on westward migration immediately after the american civil war? a) telephone b) electricity c) steam-powered boats d) transcontinental railroad

Can someone answer these question about vasco de gama for me: when? (when did he started his travel)from where & to where? (from where he was and then where he went to)motives? (what was his motives for traveling)accomplishments & discoveries? i will give you 15 star for answering all of these, you so much.