Due to the region’s low level of rainfall, Arizona Marian’s the ____________
of plant and animal life in the country.
(A) affiliation
(B) concentration
(C) alteration
(D) formation
Answer: B
D不行吗 ？ 查英英字典 formation 可以当组成 放在这里意思也通顺
国学给的解答formation 是用另一个意思 形成 所以不选D

Arizona后面那个字打错，是maintains空格前面漏打一个字“lowest”整句话：Due to the region’s low levels of rainfall, Arizona maintains the lowest concentrationof plant and animal life in the country.Google查"the lowest formation of animal life"，找不到相关结果，所以没有“最低组成”这种说法