First, we have C6. The C represents Carbon, and there are six atoms present. Next, we have H12. The H represents Hydrogen, and there are twelve atoms present. Finally, we have O6. The O represents Oxygen, and there are six atoms present.
Combined, these atoms make our lovely glucose, a form of sugar that plant produce in the process of photosynthesis.
FYI most of this information can be found on the lovely search engine called Google. ;)
Assuming purple is dominant, the genotypes of the parents must be Pp and pp, such that half the progeny have the dominant allele (P_) and half have the recessive phenotype (pp) 25% possibility of white-flowered plant life and 75% possibility of pink ones