Final answer:
To exhibit dominance, codominance, and incomplete dominance, a student should select parent plants that demonstrate each principle clearly: red and white parents that produce pink offspring exemplify incomplete dominance.
Step-by-step explanation:
To demonstrate the genetic principles of dominance, codominance, and incomplete dominance in an experiment with rose plants, the student should understand how each of these genetic interactions works using Mendelian genetics. For instance, incomplete dominance occurs when the heterozygote displays an intermediate phenotype between the two homozygous parents. This is observed when a homozygous red-flowered plant (RR) is crossed with a homozygous white-flowered plant (WW), resulting in heterozygous offspring with pink flowers (RW), thus demonstrating incomplete dominance.
When discussing codominance, this refers to the situation where both alleles in the heterozygote are fully expressed, leading to offspring with a phenotype that shows both parental traits distinctly. An example of codominance could be illustrated if the offspring have flowers with both red and white stripes or patches, reflecting the influence of both alleles equally.
Dominance is demonstrated when one allele is dominant over the other, such as when a plant homozygous for a dominant red allele is crossed with a plant homozygous for a recessive white allele, and all the offspring have red flowers.