請依下文回答第 16 題至第 20 題 Space colonization, once a topic confined to science fiction, has now become a plausible idea. With rapid advancements in technology and growing interest from both public and private entities, the possibilities of humans establishing permanent settlements in space are gaining momentum. Space colonization is driven by the vision of expanding human presence beyond Earth and ensuring the long-term survival of our species. Scientists believe that establishing self-sustaining colonies on celestial bodies such as the Moon, Mars, or even asteroids could provide a solution to future challenges on Earth, including overpopulation and resource depletion. One of the main hurdles in space colonization is the development of reliable transportation systems. Achieving routine and affordable access to space is critical for large-scale migration. The emergence of reusable rocket technology has significantly lowered the cost of reaching orbit. Moreover, ongoing research on advanced propulsion systems, such as ion engines and nuclear propulsion, could further enhance our ability to travel longer distances within the solar system. Creating habitable environments in space is another essential aspect of colonization. This involves designing closed-loop life support systems that can sustain human life for extended periods. NASA's International Space Station (ISS) serves as a crucial testing ground for developing and refining these technologies. Advances in areas like hydroponics, 3D printing, and energy generation have the potential to enable self-sufficient habitats in space. While the challenges are immense, space colonization offers several benefits. One significant advantage is the potential to exploit extraterrestrial resources. Asteroids, for instance, contain valuable metals like platinum and gold, as well as water ice, which can be utilized for life support and fuel production. By harnessing these resources, space settlers could establish sustainable economies and reduce dependence on Earth's limited reserves. The prospect of space migration also opens up new frontiers for scientific discovery. Studying celestial bodies firsthand can deepen our understanding of the universe and shed light on fundamental questions about the origin and nature of life. Furthermore, the development of technologies and methodologies required for space colonization could have far-reaching applications on Earth, benefiting industries such as medicine, energy, and materials science. In conclusion, space colonization has transitioned from science fiction to an attainable goal, opening up new possibilities for humanity. Unlocking the potential of space migration could mark a significant chapter in our history, allowing us to explore, flourish, and secure the long-term survival of our species beyond the limits of Earth.