All life is on Earth, none on Mars.
With life support, perhaps. Mars is much colder than Earth, has much less atmospheric pressure, and very little oxygen.
Mars is much smaller than Earth.
Mars is smaller and has a thinner atmosphere than Earth. Mars has a reddish color due to its iron-rich soil, and it has less gravity than Earth. Additionally, Mars has polar ice caps composed of water and carbon dioxide.
The gravity of Earth is 2.6 times that of Mars.
it cannot be too much warmer or life on earth itself would have died out
Mars tempature is much greater than earth
In the great battle between Mars and Earth, occurring over the duration of the 5th and 6th centuries, BC, Earth proved to be the more powerful planet, utterly destroying all life on Mars, and clearly evident the devoid red planet.
Mars has a much weaker gravity than Earth.
No. Earth (diamater 12,756km) is much larger than Mars (diamater 6,787km).
Mars and Venus are the two planets that possibly had life. Venus is thought to have been much cooler back then and have an atmosphere similar to that of Earth, as well as liquid water. Mars has a good enough temperature currently, and ancient Mars was thought to be like a clone of Earth today. You could say Venus Earth and Mars are the three (or used to be) triplet planets.
Radius/diameter . . . Earth's is 1.876 as big as Mars's Surface area. . . . . . 3.521 times as much as Mars has Volume . . . . . . . . . . 6.62 times as much as Mars's Mass. . . . . . . . . . . . 9.35 times as much as Mars has Surface gravity. . . . 2.66 times as strong as Mars's
76 on Earth is 28.652 on Mars.