Answer: According to NASA, Mars as of now is unsuitable for human habitation due to its extreme environments. Though evidence has been found that bacteria might have existed in Mars back then, which also suggests that water might have been present. It was quickly disproved as it the basis of the evidence was lacking in substance. Mars will only be able to sustain life if there would be gravity, sufficient oxygen, right temperatures, and water. All of which Mars does not offer, though it might be possible it will take drastic measures and expense. Therefore, adjusting or changing Mars environment is not possible.
