Answer:
A single organism can not see an immediate improvement in their traits. Traits of a population can, however, be improved by means of microevolution. By this, I mean natural selection. Organisms with traits that are better suited towards an environment have a greater probability of surviving, meaning that there will be a larger output of offspring with these same traits. This causes gradual change and evolution over time, as more and more offspring receive traits that allow them to survive in their environment.
I hope this is able to help you. If you have any other questions, feel free to leave a comment. I am happy to help ^_^