Question

Is being in a "habitable zone" enough to say the planet is habitable for human life? What characteristics would an Earth-like planet need to have to support life? What challenges would we face traveling to and colonizing Kepler-186f, or other Earth-like planets outside of our solar system? Do you think scientists should spend time looking for Earth-like planets before we have the technology to visit them? Why or why not?

Answer 1

It would need oxygen, plant-life, a suitable climate, as well as h20

Answer 2

It is not. Habitable does not mean to humans but in general to life forms. It just means that the range of orbits around a star within which a planetary surface can support liquid water given sufficient atmospheric pressure and that some form of organic life could develop, but this does mean that humans could live in them. They should definitely spend more time looking at them because the processes in those planets might be harmful to humans so humans shouldn't just try to visit them before understanding them.