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 ":".
However
,
when
excessive
levels
of
DNA
damage
are
present
,
they
trigger
apoptosis
.
However:O
,:O
when:O
excessive:O
levels:O
of:O
DNA:other-biologything
damage:O
are:O
present:O
,:O
they:O
trigger:O
apoptosis:O
.:O