Civilization

How often does a civilization occur? By studying that, we could look at stars that are suitable for the development of civilizations. How many new stars appear every year? Seven, but some stars are too cold and some are too hot. Only about 20% can be considered as suitable. We all know that there are some factors for species and animals to survive and reproduce, including environmental conditions, temperature tolerance range, body size, weight, diets, seasonal and daily activity, behavior, and the altitude they live. Animals migrate to find a new habitat because the change of environment and only species that have the tolerance for new environment could survive and reproduce. Human beings are the only organism that makes extensive use of technology to extend the limits of its natural tolerance range.