题干

如图是一块长、宽、高分别是6cm、4cm和3cm的长方体木块,一只蚂蚁要从顶点A出发,沿长方体的表面爬到和A相对的顶点B处吃食物,那么它需要爬行的最短路线的长是( )cm

A:61

B:85

C:97

D:109

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B

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    The Asian elephant has been respected for centuries and is still used today for ceremonies and religious purposes. It is respected, not only because it plays a role in Asian culture and religion, but also because it is a key biological species in the tropical forests of Asia.

    The Asian elephant is the largest land mammal in Asian. It is smaller than the African elephant, with relatively smaller ears. Asian elephants have a single “finger” on the upper lip of the long trunk, while African elephants have a second on the lower tip. A number of adult male Asian elephants have no tooth, and the percentage of males carrying ivory(象牙)is different from only about 5% in Sri Lanka to 90% in south India. Asian elephants keep their ears in constant motion in order to free the heat they produce. The species is reported to have well-developed hearing, vision, and smell , and they are also fine swimmers.

    Asian elephants prefer to convey something to form groups surrounding 6 to 7 related females that are led by the oldest female. Like African elephants, these groups occasionally join others to form herds, although these associations are relatively temporary.

    More than two thirds of the day may be spent feeding on grasses, but large amounts of tree bark, roots, leaves and small stems are also eaten. Crops such as bananas, rice and sugar plants are favored foods. Besides, they need to drink at least twice a day so the source of water is quite important.

    The Asian elephant used to live from modern Irap and Syria to the Yellow River in China at first, but it is now found only from India to Vietnam, with a tiny population in the extreme southwest of China's Yunnan Province. More than 100,000 Asian elephants may have existed at the start of the 20th century. The population is estimated to have fallen by at least 50% over the last 60-75 years.