What's on Mars? How can Mars be transformed to immigrate in the future?

So far, Mars is not suitable for human habitation;

The main reasons are as follows:

1. There is not enough oxygen concentration in the atmosphere of Mars, so human beings can't live.

Second, there is not a lot of liquid water available for human use on Mars.

Third, the climate of Mars is not suitable for human production activities.

But Mars is the planet most likely to be inhabited after Earth:

Mars and the earth are close to the sun. Mars is similar in size to the earth.

Mars has an atmosphere similar to that of the earth. Although the oxygen content is small, it can be converted to the same content.

There are solid water and even liquid water at the poles of Mars.

There are no highly intelligent creatures and no human competitors on Mars.

After the transformation, Mars may become the planet where human beings live.