To many web-building spiders, most of whom are nearly blind, the web is their S36 ______ window on the world, their means of communicating, S37 ______ prey, meeting mates and protecting themselves. A web-building spider without its web is like a man on an island of solid rock, totally nut of touch and S38 ______ to starve to death. So vital is the web to a spider’ s S39 ______ that the animal will continue to construct new webs daily even if it is being starved. For 16 days the starving spider builds completely S40 ______ webs. Then, as the animal gets thinner, it constructs a wider-meshed (风眼较大的) web using fewer strands. Such webs would only trap larger prey, which is more S41 ______ from the S42 ______ of a starving spider. The spider conserves energy by recycling web protein. S43 ______ .In studies with radioactively labeled materials, it was found that 95 percent of web protein reappears in the next day’s web. S44 ______. Scientists are impressed by the adaptability of the spider’s brain. If some of the existing strands are destroyed, or S45 ______. One spider will even finish building the incomplete web of another. S40