Which describes a major challenge facing the builders of the transcontinental railroad?
a.
tunneling under lake erie
b.
crossing the sierra nevada mountains
c.
spanning the grand canyon
d.
bridging the rio grande river

on 6 november american voters will elect members of the house of representatives and the senate, which together are called congress.

both houses of congress are currently controlled by the republican party, which backs president donald trump.

the democrats think they can win control of the house of representatives this year by winning a majority of seats.

doing so would let them block or delay the president’s plans by refusing to enact them.

all 435 seats in the house of representatives are up for election.

if the democrats want to take control of the house by having the most seats, they’re going to have to claim at least 23 from the republicans.

graphic: the battle for the house of representatives