The most accepted theory about the origin of earth is that it formed by a process called planetary differentiation accretion condensation mixing

The correct answer is : Planetary accretion
In Planetary accretion theory, the universe was formed by accretion process, which is the accumulation of particles into a massive object by attracting more matter, forming all kind of astronomical objects such as stars and planets

This is all you, but i can give you some topics that you could try. if it rained when you want to do something outdoors, it 'limits' that human activity. maybe you want to do an experiment that goes throughout the whole year and you have to have above freezing the entire year. this 'limits' your activity. i thought of those just off of the top of my head. something that gets to me that might be getting to you is you are thinking too hard about what to do. think simply, and if it is too simple, then bump it up just a little bit.

Exploration mission 2;