Bacteria
 
Bacteria
are
tiny
little
organisms
 
 
that
are
everywhere
around
us.
 
We
can't see
them
without
 
a
microscope
 
because
they
are
so
small.
They
are
 
in
 
the
air,
on
our
skin,
 
in
our
bodies,
 
 
in
 
the
ground,
 
and
all throughout
nature.
 
Most
bacteria
aren't
dangerous,
 
but
some
are
 
and
can
make
us
sick.