Raw
materials
are
substances
extracted
directly
from
____________________
.
____________________
materials
can
be
classified
in
three
groups
:
a
)
Animal
origin
:
____________________
,
silk
,
fur
,
etc
.
b
)
____________________
origin
:
tree
trunk
,
cotton
,
linen
,
etc
.
c
)
Mineral
origin
:
petroleum
,
sand
,
____________________
,
marble
,
iron
ore
,
etc
.
Processed
materials
are
those
materials
that
result
from
the
____________________
of
raw
materials
.
They
are
used
to
make
____________________
or
products
.
Processed
materials
can
be
classified
in
6
groups
:
a
)
Wood
and
derivatives
:
natural
wood
(
____________________
,
oak
,
beech
,
.
.
.
)
,
artificial
wood
(
chipboard
,
____________________
and
fiberboard
)
,
cork
,
____________________
and
cardboard
.
b
)
Metals
:
____________________
,
copper
,
____________________
,
bronze
,
brass
,
tin
,
gold
,
silver
,
.
.
.
c
)
Plastics
:
PVC
,
PET
,
____________________
,
.
.
.
d
)
Textile
materials
:
____________________
,
silk
,
wool
,
polyester
,
.
.
.
e
)
Stone
materials
:
marble
,
granite
,
____________________
,
.
.
.
f
)
Ceramic
materials
:
____________________
,
bricks
,
tiles
,
glass
,
.
.
.
