With no explanation, label each line with "O", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport", "building-hospital" or "building-hotel" preceded by ":".
When
growing
on
mineral
surfaces
,
some
lichens
slowly
decompose
their
substrate
by
chemically
degrading
and
physically
disrupting
the
minerals
,
contributing
to
the
process
of
weathering
by
which
rocks
are
gradually
turned
into
soil
.
When:O
growing:O
on:O
mineral:O
surfaces:O
,:O
some:O
lichens:O
slowly:O
decompose:O
their:O
substrate:O
by:O
chemically:O
degrading:O
and:O
physically:O
disrupting:O
the:O
minerals:O
,:O
contributing:O
to:O
the:O
process:O
of:O
weathering:O
by:O
which:O
rocks:O
are:O
gradually:O
turned:O
into:O
soil:O
.:O