阅读下文，完成问题。
      ①生物学家预言，21世纪将是细菌发电造福人类的时代。
      ②说起细菌发电，可以追溯到1910年。英国植物学家利用铂作为电极放入大肠杆菌的培养液中，成功地制造出了世界上第一个细菌电池1984年，美国科学家设计出太空飞船使用的细菌电池，其电极的活性物质是宇航员的尿液和活细菌。到了80年代末，细菌发电有了重大突破，英国科学家让细菌在电池组里分解分子，释放电子向阳极运动，从而产生电能。操作时还在糖液中添加某些芳香化合物作为稀释液，来提高生物系统输送电子的能力。与此同时，还要往电池里不断地充入空气，用以搅拌细菌培养液和氧化物质的混合物。据计算，利用这种细菌电池发电，其效率可达40％，远远高于现在使用的电池的效率，且能持续数月之久。即使这样，还有10％的潜力可挖掘。
      ③利用细菌发电原理，可以建立较大规模的细菌发电站。计算表明，一个功率为1000千瓦的细菌发电站，仅需要10立方米体积的细菌培养液，每小时消耗200千克糖即可维持其运转发电。这是一种不会污染环境的“绿色”’电站，而且技术发展后，完全可以用诸如锯末、秸秆、落叶等废有机物的水解物来代替糖液。因此，细菌发电的前景十分诱人。
      ④现在，各个发达国家各显神通，在细菌发电研究方面取得了新的进展。美国设计出一种综合细菌电池，里面的单细胞藻类可以利用太阳光将二氧化碳和水转化为糖，然后再让细菌利用这些糖来发电。日本科学家同时将两种细菌放入电池的特种糖液中，让其中的一种细菌吞食糖浆产生醋酸和有机酸，而让另一种细菌将这些酸类转化成氢气，由氢气进入磷酸燃料电池发电。
      ⑤人们还惊奇地发现，细菌还具有捕捉太阳能并把它直接转化成电能的特异功能。最近美国科学家在死海和大盐湖里找到一种嗜盐杆菌，它们含有一种紫色素，在把所接受的大约10%的阳光转化成化学物质时，即可产生电荷。科学家们利用它们制造出一个小型实验性太阳能细菌电池，结果证明是可以用嗜盐性细菌来发电的，用盐代替糖，其成本就大大降低了。由此可见，让细菌为人类供电已经不再遥远，不久的将来即可成为现实。 (选文有改动)

The crocodile is very dangerous but we can't harm it, because it belongs to the ____(danger) species and is facing up to dying out and needs protection.

    Easter(复活节) is still a great day for worship, randy in baskets and running around the yard finding eggs, but every year it gets quite a bit worse for bunnies.

    And no, not because the kids like to pull their ears. The culprit is climate change, and some researchers found that rising temperatures arc having harmful effects on at least five species of rabbit in the US.

    Take the Lower Keys March rabbit, for instance. An endangered species that lives in the Lower Florida Keys, this species of cottontail is a great swimmer — it lives on the islands! — but it is already severely affected by development and now by rising levels. According to the Center for Biological Diversity, an ocean level rise of only 0. 6 meters will send these guys jumping to higher ground and a 0.9-meter rise would wipe out their habitat (栖息地) completely.

    The snowshoe hare, on the other hand, has a color issue. Most of these rabbits change their fur color from white in the wintertime to brown in the summer, each designed to give them better cover from predators（捕食者）. As the number of days with snow decreases all across the country, however, more and more bunnies arc being left in white fur during brown dirt days of both fall and spring, making them an easier mark for predators. Researchers know that the color change is controlled by the number of hours of sunlight, but whether the rabbit will be able to adapt quick enough to survive is a big question. The National Wildlife Federation has reported that hunters have noticed their numbers are already markedly down.

    American pikas or rock rabbits, a relative of rabbits and hares, might be the firs' of these species to go extinct due to climate change. About 7-8 inches long, pikas live high in the cool, damp mountains west of the Rocky Mountains. As global temperatures rise, they would naturally migrate (迁徙) to higher ground — but they already occupy the mountaintops. They can't go any higher. The National Wildlife Federation reports that they might not be able to stand the new temperatures as their habitat beats up.

    The volcano rabbit has the same problem. These rabbits live on the slopes of volcanoes in Mexico, and recent studies have shown that the lower range of their habitat has already shifted upward about 700 meters, but there are not suitable plants for them to move higher, so they are stuck in the middle. Scientists are concerned about their populations.

    Native to the US, pygmy rabbits weigh less than 1 pound and live in the American West. They are believed to be the smallest rabbits in the world. Their habitats have been destroyed by development. Several populations, such as the Columbia Basin pygmy, almost went extinct and were saved by zoo breeding programs. Pygmy rabbits also rely on winter cover by digging tunnels through the snow to escape predators, but lesser snowfall is leaving them exposed.

All of this gives new meaning to dressing up in a giant bunny costume this Easter.