题目内容：
The case history of the twins appears to support the conclusion that__________.
A．individuals with identical brains seldom test at the same level B．an individual's intelligence is determined only by his environment
C．lack of opportunity blocks the growth of intelligence
D．changes of environment produce changes in the structure of the brain
参考答案：【答案仅供学习，请勿对照自行用药等】
答案解析：