What are the primary contributing factors to the Permian extinction event, and how did they interact to affect marine and terrestrial life?

Gradual climate change leading to ice ages, which affected only terrestrial life.

Volcanic activity leading to a temporary cooling of the climate, which affected only marine life.

Volcanic activity causing greenhouse gas emissions and warming, leading to ocean acidification and anoxia, affecting both marine and terrestrial life.

Meteorite impact causing wildfires on a global scale, leading to the extinction of terrestrial life.