Geology questions

I’m working on a geology question and need the explanation and answer to help me learn.

1. How did Earth and other planets form? Were planets formed in situ? Or are orbital changes relatively frequent? What determined the different deep layering of the solar planets?
2. Was there ever a collision of the Earth with another planet Theia, giving birth to our satellite?  There is compelling evidence, such as measures of a shorter duration of the Earthàrotation and lunar month in the past, pointing to a Moon much closer to Earth during the early stages of the Solar System.
3. What is the long-term heat balance of Earth? How did its internal temperature decay since it formed by accretion of chondrites? How abundant are radiogenic elements in the interior? Did a ! href=”http://news.discovery.com/space/was-earth-a-migratory-planet-120418.html” rel=”noopener” target=”_blank”>faint young sun%ver warm a îow-ball Earthü/li>
4. What made plate tectonics a dominant process only on Earth? How did the planet cool down before plate tectonics?[ref] Was the Earthàcrust formed during the early stages of its evolution or is it the result of a gradual destillation of the mantle that continues today along with crustal recycling? Is the crust still growing or does its recycling compensate for crust formation at mid-ocean ridges and other volcanic areas