Evidence for common descent comes from the existence of vestigial structures. These rudimentary structures are often homologous to structures that correspond in related or ancestral species. A wide range of structures exist such as mutated and non-functioning genes, parts of a flower, muscles, organs, and even behaviors. This variety can be found across many different groups of species. In many cases they are degenerated or underdeveloped. The existence of vestigial organs can be explained in terms of changes in the environment or modes of life of the species. Those organs are typically functional in the ancestral species but are now either semi-functional, nonfunctional, or re-purposed.
Based on the above text, what's the best answer to this question: the presence of vestigial structures is explained by the common descent hypothesis. true false?

OPTIONS:
(I) no
(II) yes
(II)