Dear student ...... Incomplete dominance is a form of intermediate inheritance in which one allele for a specific trait is not completely expressed or completely dominant over its paired allele............ This results in a third phenotype in which the expressed physical trait is a combination of the phenotypes of both alleles..............Ex .....In a cross between true-breeding red-flowered (RR) and true breeding white-flowered plants (rr), the F 1 (Rr) was pink....... When the F1 was self-pollinated the F 2 resulted in the following ratio 1 (RR) Red : 2 (Rr)Pink: 1 (rr)White, the phenotype ratios had changed from the 3:1 dominant : recessive ratio because R was not completely dominant over r and this made it possible to distinguish Rr as pink from RR (red) and rr (white) . ........With regards ....mahima.(Askiitians forum expert )