According to descartes, when a sense receptor is stimulated, "delicate threads" are pulled and cavities in the brain are opened, thereby releasing into the nerves.

Guinea pig coat color is determined by a single gene. the allele for black coat color is dominant to brown. in a cross between twoblack-haired guinea pigs, 20 offspring are born. if both parents were heterozygous, probability would predict that approximately howmany of the 20 offspring would have brown hair?