Arecessive allele a. occurs as a regulatory gene only b. needs to be present on only one chromosome to be expressed c. is never expressed d. needs to be present on both chromosomes to be expressed

D: needs to be present on both chromosomes to be expressed

Why: Because if there was a dominant trait present, then the dominant trait would overpower the recessive trait regardless of the matter.

emerging idea only occurs as a raw idea that could appear out of nowhere. meanwhile, to reach scientific consensus , that idea must be structured and tested over and over again through various experiments. the scientific consensus transforms the raw idea into idea that is more reliable through the process of scientific elimination.