The Cambrian Explosion is when diverse animals were first recorded as fossils.
The resin why our brain changes throughout our life time as human beings, is simply because of age. Whatever you might learn, or adapt to it will all effect the brain. Everything you do is what your brain makes you do, and it changes with everything you do it all has a huge impact on your brain. Everything, its all about age and time. Hope this was helpful !!
Because we do or we would die