Snapdragon is also known as the dog flower. Here the dominant allele is R and is responsible for red color flowers, and r is the recessive allele responsible for white color flowers. Now R expresses itself in homozygous as well as in heterozygous conditions whereas r expresses itself only in homozygous conditions. One  Parent flower is red and the other parent flower is white, in the F1 generation, all flowers were pink due to the incomplete dominance of the red flower.