Anumber of single gene mutants in mice have been discovered that all influence the development of the cerebellum. the weaver mutant shows granule cells in the external granule cell layer instead of in the internal granule cell layer. the external layer is where cell division takes place and the internal layer is where mature granule cell layer. the external layer is where cell division takes place and the internal layer is where mature granule cells are positioned to form neural circuits. which developmental process is compromised by the weaver mutation?
a. cell division
b. cell migration
c. trophic interactions: circuit validation
d. regional patterning
e. none of the above