With no explanation, label each line with "O", "other-biologything", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
The
exact
mechanism
in
early
embryogenesis
that
induces
cells
to
differentiate
is
still
unclear
,
but
this
mechanism
has
been
closely
linked
to
protein
kinase
A
(
PKA
)
.
The:O
exact:O
mechanism:O
in:O
early:O
embryogenesis:O
that:O
induces:O
cells:O
to:O
differentiate:O
is:O
still:O
unclear:O
,:O
but:O
this:O
mechanism:O
has:O
been:O
closely:O
linked:O
to:O
protein:O
kinase:O
A:O
(:O
PKA:other-biologything
):O
.:O