Because there is no water,oxygen,food.
If you were to just put a person on Mars, then no. There is no oxygen on Mars, and oxygen is essential to human life. However, if there were buildings which could provide the oxygen, similar to a space station, and there is plenty of food, then yes it is possible for a human to survive on Mars.
no water, weak greenhouse effect (if any, don't remember), too cold.
no Yes it does.
Maybe
No. Mars is too cold for human life and the air is not breathable. There is no magnetic field to shield against solar radiation.
It is possible that very primitive life could survive on Mars, but not advanced life leading to anything like humans.
Yes, there is oxygen on Mars. However there is not enough to support human life.
Because Mars does not have an atmosphere suitable for human life.
no where, but there was a machine that had went to Mars and was said that there could be life in Mars... :)
It is currently not possible for a human to survive on Mars without protective gear and specialized systems due to its extreme cold temperatures, thin atmosphere, lack of oxygen, and high levels of radiation. Future colonization efforts would require advanced technology to support human life.
Yes
No. Humans only live on Earth. There is likely no life at all on Mars.