One Kia’s Current understanding:
Biological Evolution is both a process and a function of population genetics whereby biological life forms change and are modified as a species group over time in response to their environments, even their changing environments, both by the passing on of more ‘advantageous-for-survival- in-their-environments’ mutations’ and by the ‘selection out’ of individuals less equipped and ‘fitted’ to pass on their genes to the next generation.
Life itself is “plastic” to the environments it lives in, and over time and successive generations… changes and Evolves to fit the environment in order to both survive and thrive to continue into the next generations.
Evolution is a Fact of Life like Gravity is a Fact of Physics or Germs causing disease is a Fact of Biology and Medicine. Even though all of these are referred to as Theories, NONE of them are “just a Theory”. They are Indisputable and incontrovertible Facts.
Deal with it.