EARTH AND SPACE
STRATIGRAPHIC LAYERS
GEOLOGICAL TIME SCALE
MAJOR STAGES IN THE HISTORY OF LIFE ON EARTH
EXTINCTIONS
FOSSILS
SCALE OF THE UNIVERSE
CONDITIONS CONDUCIVE TO THE DEVELOPMENT OF LIFE
STRATIGRAPHIC LAYERS
GEOLOGICAL TIME SCALE
MAJOR STAGES IN THE HISTORY OF LIFE ON EARTH
EXTINCTIONS
FOSSILS
SCALE OF THE UNIVERSE
CONDITIONS CONDUCIVE TO THE DEVELOPMENT OF LIFE