Is it likely that scientist can live outside of earth for
along period of time, with only sustaining themselves wtih
oxygenfrom plants in which they carried with them to the
outerjourney?

It is likely that scientist can live outside the earth but not for a long time. They can sustain themselves with oxygen from plant, but not for long. The planet outside the earth is harsh, and not favourable to human and plant. The only way they can survive is to grow the plants In a controlled environment.

Explanation:

the atomic number will stay the same no matter how many electrons it has, so it doesn’t decrease nor increase. it’ll only change with a different number of protons

the answer is minerals.