Answer:
Water
Explanation: I think this is the answer if I am wrong please tell me thank you.
Answer:
D) A Survey of fellow classmates
Explanation:
This is the correct answer because an informal survey involves various answers that may or may not be accurate. Informal surveys cannot be held as scientific fact and are, therefore, not reliable. A scientific journal is reliable because it most likely includes data from an experiment and/or research of a trusted scientist or group. The results of past experiments are very reliable because these are the results of hard work and thorough planning and research. A scientific discussion with colleagues is not very credible because it involves the sharing of opinionated information, but it is certainly more reliable that the varying answers of school-aged peers.
I believe the biggest space mission of the twenty-first century will be a manned mission to Mars, and the colonization that follows. This is the stated goal of several nations, companies, and individuals, all with considerably deep pockets. This mission will not only be a huge leap forward in space exploration, it will usher in a new era in human history in which the human race is an interplanetary civilization, a natural milestone as humanity continues to progress and advance.
Significant challenges are many and overwhelming. In terms of getting to mars, we need efficient, powerful propulsion systems and a spaceship that can not only accommodate a full crew for a mission that would likely last years, but withstand the various hazards that a long trip through space and entrance into the Martian atmosphere will entail. In terms of colonization, significant challenges will include establishing efficient and frequent travel/transport between the planets, and in the longer term, the necessity to terraform the planet (make it more like Earth) so that humans can more easily live there.
