Dung beetles ______ an integral part of the successful management of diary farms in Austra
A.has become
B.have become
C.became
D.had become
A.has become
B.have become
C.became
D.had become
第2题
A.Y
B.N
C.NG
第3题
Why do researchers estimate elephant numbers in an area by counting dung piles?
A.Because elephants are difficult to catch
B.Because it is not possible to count elephants from a plane.
C.Because it is not possible to keep track of elephants.
D.Because elephants are shy animals
第4题
A they are different in size
B they scatter an over the region.
C they are different in decay rate.
D they are different in quality.
第5题
Why did the farmers become desperate in the mid 30s?
A.Their houses were destroyed by cane beetles.
B.Cane beetles dropped their eggs onto the ground around the base of the plant.
C.Cane beetles killed all their livelihood.
D.Their sugar cane plants were ruined by overwhelming beetles.
第7题
The grass minerals in the Indian dung fossils are of oldest minerals on record,
A.Y
B.N
C.NG
第8题
A.Y
B.N
C.NG
第9题
Why do researchers estimate elephant numbers in an area by counting dung piles?
A.Because elephants are difficult to catch.
B.Because it is not possible to count elephants from a plane.
C.Because it is not possible to keep track of elephants.
D.Because elephants are shy animals.
第10题