Nearly
all
our
food
comes
from
the
soil.
Some
of
us
eat
meat,
of
course;
but
animals
live
on
plants.
If
there
were
no
plants,
we
would
have
no
animals
and
no
meat.
So
the
soil
is
necessary
for
life.
The
top
of
the
ground
is
usually
covered
with
grass
or
other
plants.
There
may
be
dead
leaves
and
dead
plants
on
the
grass.
Plants
grow
in
soil
which
has
a
dark
color.
This
dark
soil
is
humus.
Humus
contains
materials
taken
from
dead
plants,
and
the
waste
matter
from
animals
also
falls
on
it.
This
gives
it
its
color.
The
soil
under
the
humus
is
not
dark.
This
lighter
soil
is
rather
like
sand;
it
is
made
of
bit
of
rock.
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