17．
Do you know what the hump（驼峰） of a camel is used for？If you answered to store water，guess again．In fact，a camel's hump is a place for storing fat．
Most animals，including humans，store fat throughout their bodies，under their skin．But camels store their fat in one place，their hump．A hump can weigh as much as 80pounds．Why do camels keep their fat this way？The answer is most likely because of their environment．Camels can go up to two weeks without eating because they have this fat to live off．
Also camels are great at handling（处理，应付） changes in body temperature．Their humps can help the camels keep cooler．Their coats also help them adapt（适应） to the heat．While the coat is thick，it reflects（反射）the sunlight and protects the camel from the heat that rises off the desert sand．
There are two kinds of camels，those with one hump and those with two humps．Camels with one hump are called Dromedary or Arabian camels．They live in the dry deserts in West Asia．Camels with two humps are called Bactrian camels．They live in Central and East Asia．
Besides their humps，camels have a lot of interesting facts．They can live between 40～50years．They can carry about 400pounds and run up to 40miles per hour．It's true that camels can go long time without drinking water，and they can drink about 26gallons of water at a time．Camels can also close their nostrils（鼻孔）．So whether a camel has one hump or two，it is one amazing animal that is very well adapted to its environment．
43．What is a camel's hump used for？B
A．Storing water．
B．Storing fat．
C．Carrying food．
D．Carrying riders．
44．From the passage we can learn thatC．
A．camels'humps are very interesting
B．camels'humps can make them amazing
C．a camel's hump can weigh as much as 80pounds
D．camels with two humps are called Dromedary camels
45．Which is the best title of the passage？B
A．Interesting humps
B．One hump or Two？
C．Great animals
D．Two kinds of camels．
