The
____________________
from
Asia
to
North
America
across
the
Bering
Strait
was
a
____________________
event
in
human
history
.
The
process
of
overspreading
the
Americas
took
more
than
1
,
000
years
,
or
30
____________________
.
This
process
was
____________________
fast
-
about
10
miles
per
year
,
on
average
.
The
Americas
were
populated
at
an
____________________
pace
,
when
one
considers
the
physical
limits
of
the
human
body
and
the
physical
____________________
of
the
American
continents
.
Legs
of
humans
can
____________________
only
so
fast
under
the
best
of
____________________
,
and
they
work
even
slower
over
mountain
passes
or
____________________
.
Populations
spread
through
the
diverse
____________________
of
the
Americas
(
grasslands
,
eastern
forests
,
coastal
swamps
)
and
needed
to
____________________
to
their
new
environments
.
The
migrants'
lifestyle
had
evolved
over
the
years
to
that
of
professional
nomads
ensuring
that
they
would
find
the
resources
needed
to
____________________
.
