The allele that can mask the presence of another allele is called dominant. The allele that is masked is recessive and if both alleles can be detected in the phenotype, then they are codominant. If they produce an intermediate phenotype like pink instead of red or white, then they have a relationship of incomplete dominance.
Photosynthesis and cellular respiration are complementary because both depend on the inputs and outputs of both processes to continue. Photosynthesis requires CO2, which cellular respiration outputs and cellular respiration needs oxygen which photosynthesis makes.
