Answer:
The major difference between the Big Bang theory and the steady state model is that the the big bang theory comes with the belief and idea that all the matter were created as a result of one big bang explosive beginning.
The steady state model matter however talks about matter being created at a steady rate through a specified time. The model also talks about the process being continual and is still happening till today.
The first three answers are natural changes, while the last three are because of human intervention.