The scientists they are pretty sure Mars had water and oxygen one time, maybe lakes Oceans, Lake and Rivers. The iron oxide — the same compound that gives blood and rust their hue, everything on Mars got iron "oxidized" and at some point in history the air and seas of Mars changed. They are pretty sure Mars has a tiny magnetic field, compared to Earth which has a strong field that protects against Earth vs Solar storms creating Aurora at the poles. Mars probably had a lot of its atmosphere stripped away by Solar storms over time, it also became less geologically active, there are probably Volcanoes active today on Venus on the Moons of Titan on Europa, it is also a lot closer to the asteroid belt which could have left it vulnerable to planetary changes by impacts. https://en.wikipedia.org/wiki/Asteroid_belt