Container
ships
transport
a
combination
of
two
____________________
container
sizes
known
as
20
-
or
40
-
feet
equivalent
units
.
The
____________________
are
carried
in
cellular
____________________
and
stacked
on
the
ships
hatch
covers
and
upper
____________________
.
The
contents
of
the
containers
can
be
non
-
perishable
,
or
perishable
,
with
the
latter
often
being
carried
in
____________________
containers
.
Container
shipping
generally
operates
according
to
regular
____________________
on
set
routes
,
known
as
?
liner
?
services
.
For
this
reason
,
the
sector
is
sometimes
referred
to
as
?
liner
shipping
?
.
____________________
ships
have
played
a
key
role
in
the
____________________
of
products
over
the
past
twenty
years
,
enabling
consumer
goods
and
products
to
be
____________________
in
developing
,
lower
cost
countries
for
____________________
to
higher
cost
countries
.
