The two main factors are: A breathable atmosphere and liquid water. The planet also should be in the "Goldilocks zone" or Habitable zone. Without a breathable atmosphere like ours, there would be no life. That is also a reason why NASA haven't found anything or life in Mars. Mars is full of carbon dioxide (CO2).
Earth
Mars' moons have no atmosphere
Distribution of methane is in the atmosphere of mars.
Venus has a low atmosphere and it is rally hot
Yes, all planets have atmosphere but to my knowledge mars' is not breathable.
Cotton is a breathable material. The atmosphere of Mars is not breathable by humans, yet.
Breathable atmosphere, lots of fur coats, algae, water, and impenetrable shelter.
No breathable atmosphere No protection from ultraviolet rays No food No readily available water
It would not be easy to live on Mars since it does not have a breathable atmosphere, however, with sufficient technological support, it is possible to live on Mars.
No, there is not.
Mercury does not have a breathable atmosphere. There is no planet in our solar system that offers an atmosphere that humans can breathe.
The atmosphere of Mars contains trace amounts of oxygen; not nearly enough to make it breathable for humans.
The two main factors are: A breathable atmosphere and liquid water. The planet also should be in the "Goldilocks zone" or Habitable zone. Without a breathable atmosphere like ours, there would be no life. That is also a reason why NASA haven't found anything or life in Mars. Mars is full of carbon dioxide (CO2).
Compared to the planet Earth, it is always winter on Mars. The length of the seasons is not likely to affect people. The lack of a breathable atmosphere will be a much more pressing concern.
There is no air on the moon. Its atmosphere is so thin as to be nearly undetectable. Without bringing oxygen from the Earth the astronauts would have perished.
No it is not breathable, because the planet is full of dangerous gases such as methane.