Answer: sunlight and carbon dioxide
Explanation:
I THINK C.) anaerobic bacteria
Purple is dominant to white flowered.
Purple gene(which occurs in pairs of PP which are both dominant alleles) crossed with a recessive pp(white flowered) after crossing, all the offspring had Pp. Purple being dominant suppressed the white(p).
after crossing the offspring, (Pp and Pp) a quarter the offspring lacked the dominant allele P hence allowing the recessive colour white to be shown.