The following lists the steps between the Siberian traps and mass extinction. Choose the answer that puts the steps in the correct order. [1] As hydrogen sulfide accumulated in the ocean, the poisonous gas escaped into the atmosphere. [2] Carbon dioxide in the atmosphere trapped heat, causing global warming. [3] Hydrogen-sulfide producing bacteria thrived in the anaerobic oceans. [4] Mass extinction occurred on the land and in the water due to hydrogen sulfide poisoning. [5] Ocean waters lost oxygen as the oceans warmed up. [6] Volcanoes released mass quantities of carbon dioxide into the atmosphere.