What part did the steel industry play in the growth of american industry?

The
United
States
emerged
as
an
industrial
giant
in
the
decades
after
the
Civil
War.
Old
industries
have
expanded
and
many
new
ones
have
emerged,
including
the
refining
of
petroleum,
steel
production,
and
electrical
power.
Railroads
significantly
expanded,
bringing
even
remote
parts
of
the
country
into
a
domestic
market
economy.
American
society
has
been
transformed
by
industrial
growth.
It
has
produced
a
new
weal
class

Are their any multiple answer's ?