There are currently three living species of elephants： the African Bush Elephant, the African Forest Elephant and the Asian Elephant or Indian Elephant. Other species such as the mammoths （猛狙象）1______ before the last ice age but are now 2 ______.
Elephants live in a structured social order. 3______ females spend their entire lives in tight- knit family groups 4______ mothers, daughters, sisters and aunts, males live mostly solitary lives. Elephants 5 ______ live for 50 to 70 years. The elephant's pregnant period is 22 months, the longest of 6 ______ land animal. Newborn elephant calves weigh 7______260 pounds.
Elephants spend about 16 hours a day finding and eating food. Their diet consists 8______ grasses, leaves, bamboo, twigs, bark, roots and small amounts of fruits, seeds and flowers.Interestingly, elephants only digest 40% of 9______ they eat； an adult elephant can consume 300-600 lb of food a day.
Elephant skin is thick, grey and wrinkled. The wrinkles help elephants stay cool 10______ water gets trapped inside the wrinkles and evaporates slowly. Their hearing is 11______ and they can detect noise from miles away.
One of the most distinct 12______ attributes of elephants is their tusks. Elephants use their tusks to dig for food, mark their 13______ and perform other tasks. Elephants' tusks are made of ivory. The 14______ elephant ivory is one of the major reasons people hunt elephants and thus have significantly 15______ the world's elephant population. For this reason and many others. many people around the world are working hard to protect the species from further extinction.
11
A.weak
B.lost
C.normal
D.keen
正确答案是D