请教一句话的意思

呃~~可是这么理解的话还是不明白题目的意思哦~~下面是原题，帮忙解答一下吧~~~大谢哦~~

If the artificial is not better than the natural, to what end are all the arts of life? To dig, to plow, to build, to wear clothes—all are direct violations of the injunction to follow nature.

17. Which one of the following is an assumption made by the author of the passage?
(A) The arts of life have no useful end.
(B) The artificial is not better than the natural.
(C) Digging, plowing, building, and wearing clothes are better than nature.
(D) The injunction to follow nature should not be violated.
(E) The arts of life are indirect means of following nature.

18. If the author’s argument were challenged on the grounds that the construction of buildings has adverse effects on the natural environment, which of the following replies might the author use to respond to the challenge logically?
(A) There are human activities, such as making music, that are environmentally harmless.
(B) Harming the environment is not an end, or purpose, of the arts of life.
(C) The construction could involve the use of natural, not artificial, materials.
(D) Constructing buildings is not an “art of life.”
(E) Even if the natural environment is disturbed by the construction of buildings, it is improved for human use.

第17题答案是C，第18题是E。因为理解不了原文的含义，所以怎么都不明白这两道题目是怎么回事~~真的很头疼呢~~