The most important characteristic of a CAS is that it evolves continuously. Let's take human beings as an example. We, as a CAS, have evolved over millions of years from apes to our current form. We have shed the tail, as it was of no use to us. We branched into multiple races. We are still evolving and will continue to do so. Another example is economies, which were long ago based on a barter system and then went on to paper and credit money and now seem to be moving toward cryptocurrencies. The evolution of a CAS keeps pace with the changes in the environment. This is the primary reason for the resilience in a CAS, which significantly improves its chances of survivability.