SORU: aşağıdaki parçaya göre cevaplayınız
According to the passage, in the recycling of waste paper, ----.
The world now recycles just over 50 per cent of the
paper it uses. Reprocessing plants are being
established in most countries. However, trees will
never be fully spared because of the use of wood
fibres themselves. Pure pulp is rich in water, which
provides for ample hydrogen bonding that holds
fibres together when made into paper. But each time
a fibre is cleaned, de-inked and dried in a
reprocessing plant, only 80 per cent of the bonds are
recovered. After four or five recyclings, a fibre can no
longer make strong enough bonds. Engineers can do
little that is economically viable to overcome this
physical limitation, so they focus on reducing the cost
of reprocessing fresher fibres. One main challenge is
finding a better way to neutralize “stickies”, which is
the mess of adhesives from stamps, labels, seals,
tape, magazine spines and various other sources,
that jam the machinery. The industry has been
working for a decade to find a chemical process that
will break down stickies, but no full solution has been
found yet.