18 According to the passage, which of the following about space colonization is correct?
(A) Space colonization is mainly driven by the desire to study the origin and nature of life on Earth.
(B) Reusable rocket technology has prominently contributed to lowering the cost of reaching space.
(C) Closed-loop life support systems play an insignificant role in sustaining human life in space.
(D) Space colonization has seemingly negligible potential benefits for certain industries like energy.

根據文章，以下哪一項關於太空殖民是正確...