91色情片

Skiers can now do less damage as they race down the slopes, thanks to a wax
made from soya beans. Usually, skiers spread a paraffin-based wax on their skis
to help them speed over the snow. When the snow melts, traces of the paraffin
can be washed into local water supplies. Now students from Purdue University in
Indiana have come up with a petroleum-free wax that can be used to cut the drag
from skis.