Background color for WARNING safety signs, labels, and tags. Marking hazardous parts of machines with may cut, crush, or otherwise injure. Emphasizing hazards when enclosure doors are open or when gear, belt, or other guards around moving equipment are opened or removed, exposing unguarded hazards. Marking exposed edges of
Bibcode:1995GBioC...9..377C. doi:10.1029/95GB01107. An ice age is a period of long-term reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers.
Paleolithic timeline - Paleolithic lifestyle - Paleolithic life expectancy. The Paleolithic era is also fondly known as the Stone Age period. It existed between (2.5 million - 20000 years ago). The era was beginning of small innovations carried on within the group for survival. It began with preparing and manufacturing tools and hunting.