I am not sure what you mean by 'depend' (please try and make your questions clear) but if you mean does the fact that a helium filled balloon will float (or rise) depend on gravity? Then the answer is Yes. if you were to take a helium filled balloon to the space station and release it inside, it would not rise, it would behave just the same as if you released a bunch of keys.
nope. just the heleum in the balloon
heleum
Heleum oxyde
i would love to answer that, but it's your homework.
The theory explaining planetary formation was ideated in the late 19th century. It's true that it has undergone a lot of modification since then to include what we've learned through observation and a bit of calculation. But the center of the idea is that at some point in time, gaseous components in a molecular cloud or nebulosity are pulled together and concentrate due to gravity. Then a long period of accretion sees the formation of a star and an associated planetary system. This is the nebular hypothesis. As more and more time passes, enough material "clumps together" that a gravity well forms and "gathers" all the material in the vicinity. Separate gravity wells "stake claim" to volumes of space around a central point where a star forms. Eventually, enough material gathers and gravity becomes high enough to form everything into a sphere, as planets are shaped in a ball because it is the most efficient response to that much gravity. Use the link below to learn more. it is a hard formula