Final answer:
The establishment and evolution of Earth's four basic subsystems were caused by a variety of factors, including chemical variety, collisions with smaller bodies, changing atmosphere, and cosmic debris impacts.
Step-by-step explanation:
The establishment and evolution of Earth's four basic subsystems were caused by a variety of factors. One major factor is the chemical variety and moderate conditions on Earth, which led to the formation of molecules that could reproduce, essential for beginning life.
Over billions of years, life evolved and became more complex, punctuated by planet-wide changes caused by collisions with smaller bodies. Another factor is Earth's changing atmosphere and the influence of cosmic debris impacts, which have shaped the evolution and diversity of life on our planet.