Ostrich chicks reared on farms（）

单项选择题The author believes recent discoveries of the remains of complex societies in Amazonia（）

A.are evidence of early indigenous communities.
B.are the remains of settlements by invaders.
C.are the ruins of communities established since the European invasions.
D.show the region has only relatively recently been covered by forest.

单项选择题The assumption that the tropical ecosystem of Amazonia has been created solely by natural forces（）

A.has often been questioned by ecologists in the past.
B.has been shown to be incorrect by recent research.
C.was made by Peter Feinsinger and other ecologists.
D.has led to some fruitful discoveries.