mutation of genes hybridization of species extinction of populations alteration of the environment
I gave my students this multiple choice question: Evidence suggests that there is a relationship between ancient dinosaurs and modern birds. Through time, each occurrence of a new trait most likely resulted from which of the following?

Only one answer is correct among these 4 choices:
- mutation of genes
- hybridization of species
- extinction of populations
- alteration of the environment

Could you tell me which one is correct?

mutation of genes