Ecosystems
consist
of
a
____________________
____________________
,
living
things
and
the
____________________
among
them
and
the
environment
.
Physical
environments
can
be
____________________
or
____________________
.
All
living
things
are
grouped
into
____________________
.
All
the
organisms
of
one
species
in
an
ecosystem
make
up
a
____________________
,
and
all
the
populations
of
an
ecosystem
make
up
a
____________________
.
Organisms
that
produce
their
own
food
are
called
____________________
.
Organisms
that
feed
on
other
living
things
are
called
____________________
.
These
can
be
primary
,
secondary
or
tertiary
.
____________________
feed
on
dead
animals
.
____________________
break
down
dead
plant
and
animal
materials
.
Interactions
among
living
things
in
an
ecosystem
also
include
other
types
of
relationships
,
which
can
be
beneficial
,
like
____________________
and
commensalism
,
or
harmful
,
like
____________________
and
competition
.
