Final answer:
If all planets had a livable environment, it could lead to increased exploration and habitation of other planets, and possibly colonization and migration. However, this is speculative and there is no conclusive evidence available. Universal peace and cooperation among planets would depend on various factors.
Step-by-step explanation:
If all planets had a livable environment for people, it would likely lead to increased exploration and habitation of other planets. Colonization and migration between planets could also occur as humans seek to take advantage of the livable environments. However, it is important to note that this is purely speculative as there is currently no conclusive evidence available to support these scenarios. Universal peace and cooperation among planets is not guaranteed and would depend on various factors.