Answer:
Answer is B. norm of reaction for height.
Explanation:
Genotype can be explained as the genetic constitution or collection of genes which are responsible for many genetic characters of an individual.
In this case, the effect a genotype which produces tall plants at low and high elevation as well as short pants at medium elevation is considered as normal reaction of the gene for height.
It should be noted , that genotype is different from phenotype, because the phenotype are expressed characters or features.
