参考答案

正确答案：A
解析：本题为推理题。要求说明根据Denis Park的论述可以得出什么样的结论。根据文章最后一段的“Ms．Park says mental performance is a direct result of brain activity and brain structure．She says older people should take part in activities that keep their brain active．”可以得知A．mental performance can be improved为正确答案。而选项B．mental ability is determined entirely by brain structure、应分析选项C．people of different ages use different parts of the brain for memorizing和选项D．different parts of the brain are responsible for different mental activities则都是一般性常识，本文并没有就这些问题进行说明，因此均不符合题意。