TEXT A To many web-building
spiders, most of whom are nearly blind, and the web is their essential window on
the world：their means of communicating, capturing prey, meeting mates and
protecting themselves. A web-building spider without its web is like a man
marooned on an island of solid rock, totally out of touch and destined to starve
to death. So vital is the web to an orb-web spider’s survival
that the animal will continue to construct new webs daily even if it is being
starved. For 16 days the starving spider builds completely normal webs. Then, as
the animal gets scrawnier, it constructs a wider-meshed web using fewer strands.
Such webs would only trap larger prey, which is more economical from the
perspective of a starving spider. The spider conserves energy by
recycling web protein. It simply eats its own web each evening and re-uses it to
manufacture new silk. In studies with radioactively labeled materials, it was
found that 95 percent of web protein reappears in the next day’s web. Most of
the energy needed for web-building is used in walking over the strands as they
are laid down. Scientists are impressed by the adaptability of
the spider’s highly preprogrammed brain, which is larger for its size than the
brain of any other invertebrate. If web-building is interrupted, or if some of
the existing strands are destroyed, the spider simply retraces its steps to see
where the web is left off and then finishes building a normal web. One spider
will even finish building the incomplete web of another. That a spider is able to finish an incomplete web of another proves that ______.
A．a spider re-uses its web protein to reproduce new silk B．spiders have a highly preprogrammed brain C．the web is everything to a spider D．a spider is able to remedy a destroyed web