No. As of current known orbital data, the Earth will never be in a position to collide with another planet.
Astronomers have found Earth-sized planets in other solar systems.
Since no one from Earth has visited another planet, and we have no indication that there is anyone on the other planets, Earth does not help other planets in any way. Why do you think there is something Earth does to help them- whoever them is.
No, there is no oxygen on any other planet other than Earth because there is no planet life on the other planets.
Earth, Venus, and Mercury are also inner planets.
Yes, only on the Earth. We don't know if the other planets have life
Other than the Earth, no life has been found on any of the other planets. We are still searching.
All planets have gravity- Some more than Earth, some less. Other planets that are large enough do have air- but not made up of the same gasses as Earth.
You will not pass any planets on the way from Venus to Earth because both planets are right next to each other, except if you count Venus and Earth as passing from one to the other.
We don't know about any other other place, besides Earth, that harbors life. But many scientists think that there is life on other planets.
Earth, the Moon, the Sun, other planets.
All planets have gravity, not just Earth.