Deducing a genotype : if assuming ptc as a simple gene trait, what other genotype would you select to put in this missing genotype box that could result in this phenotype ? why ?

answer; polycythemia is the correct answer;

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.