In what ways can you terraform Mars?
The atmosphere composition of Mars is 95% CO2 and 5% N2. In this way, you can’t simply plant trees on it in hope of them miraculously producing oxygen. Because they will all die with no O2 at all. Elon Musk is preparing to send people onto Mars. The best possible option we can now make, yet still very very challenging, is to make a remote station there with enclosed protective shell. And we have to bring tons of oxygen and pump them periodically inside the station in order for every living thing in there to stay alive.