how can mutant version of organisms assist scientist in understanding how normal physiological process take place.

CancerWhy, in the two-hit model of cancer, is a germ cell/ somatic cell mutational combination morelikely than two somatic cell mutations?Considering that cancer is caused by mutations in tumour suppressor and/or proto-oncogenes,how might RNAi be used to treat cancer? Give a general example.Explain how Retinoblastoma appears dominant in pedigrees, when in fact the mutationsunderlying this cancer are recessive?