Respuesta :
Answer: a. Natural selection
Natural selection is a process by which organisms with characteristics suited to the environment will survive and reproduce. Natural selection favors the survival and reproduction of individuals having phenotypic characteristics suitable for survival in a particular environment. Darwin has given example of beetle population having two different colors: red and green. Those having green color mimic the color of grass and were not observed by the crow population but those in red color were observed and eaten up by the crow population. Hence, green color was a phenotypic advantage to these beetles which helped them to survive and increase in number through reproduction.