Rocks were eroded to form soil. Molten rock warmed Earth's interior. Earth's gravity accumulated to modern levels. Volcanoes exploded to form mountaintop lakes.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Before large trees could grow on Earth, what had to happen first?
Possibilities:
- Rocks were eroded to form soil.
- Molten rock warmed Earth's interior.
- Earth's gravity accumulated to modern levels.
- Volcanoes exploded to form mountaintop lakes.

Rocks were eroded to form soil.