SORU: aşağıdaki parçaya göre cevaplayınız
The passage suggests that the long natural lifespan of the crow ----.
Crows are black birds, and they are very ugly. But
they are also very clever. Or perhaps, since they
have extremely long lives, they have time in which to
collect a great deal of information. For instance, they
have developed an excellent method of getting
walnuts out of their shells. The first stage was to drop
them from a height. If they fell on a soft surface they
didn't break; if they fell on a hard surface like a road,
they often did. If they didn't, however, passing cars
would crush the walnuts. But one problem remained.
It is difficult for a crow to eat crushed walnuts when a
lot of cars are passing. In the end, this problem, too,
was solved. They started to drop the walnuts just
ahead of the traffic lights.