Within 20 years it will probably be possible to identify the genetic susceptibility an individual may have toward any particular disease. Eventually, effective strategies will be discovered to counteract each such susceptibility. Once these effective strategies are found, therefore, the people who follow them will never get sick.

The argument above is based on which of the following assumptions?

(A) For every disease there is only one strategy that can prevent its occurrence.

(B) In the future, genetics will be the only medical specialty of any importance.

(C) All human sicknesses are in part the result of individuals’ genetic susceptibilities.

(D) All humans are genetically susceptible to some diseases.（C）

(E) People will follow medical advice when they are convinced that it is effective. 答案是C, 理解上有一个问题，感觉这个答案很勉强 C 说 in part， 也就是说所有人类的疾病都部分因为个人的基因情况。

个人理解C实际上起到的削弱作用，因为所有人类的疾病都有部分归因于基因问题，也就是说，还有其他和基因无关的问题，譬如天气因素。这样的话，即使基因技术在发达，也不可能修复这些和基因无关的因素。

我这样的理解是过多的引用了常识进行推广，还是文字理解错误，或是其他？

谢谢

It's an assumption question so you can try "deny-test'. Deny C, we get "Not all sicknesses are in part the result of individual's genetic susceptibilities". If so, people following all the counter-susceptibility strategies may still fall on sicknesses not related to genetic susceptibility. The original conclusion would fall apart. Therefore, C is a necessary assumption.