Answer: The correct answer for the blanks are- 1) Dominant and 2) Blending of the trait.
Incomplete dominance produces a blend/ intermediate phenotype of both the parental phenotypes ( such as Pink snapdragon here) because none of the parental allele completely masks the effect of other.
As per the given information in the question, when true-breeding, red snapdragons are crossed with true-breeding white snapdragons, they produce pink colored offspring. This means that neither of the parental gene is dominant over the other.
When both are cross bred, they will represent a heterozygous state ( when alleles for both the snapdragons are present ), and they will produce an intermediate phenotype ( that is a blend of both the traits). This represents blending of the parental trait.