What describes the influence of environmental factors on the expression of genes?

Phenotypic plasticity refers to the ability of an organism to change its phenotype in response to environmental conditions. This concept highlights the dynamic interaction between genotype and environment, showing how the expression of genes can vary based on different external influences. For instance, a plant might grow taller in a nutrient-rich environment compared to a more barren one, even though its genetic makeup remains unchanged. This adaptability is a crucial aspect of survival and evolution, demonstrating how organisms can modify their physical characteristics or behaviors when faced with varying environmental conditions.

While phenotype generally refers to the observable characteristics resulting from the interaction of genotype and environment, phenotypic plasticity specifically emphasizes the flexibility in expression due to environmental factors, making it the most fitting choice for this question. Genotype, which pertains to the genetic makeup itself, does not address how those genes are expressed in varying conditions, and allelic variation focuses on differences in gene alleles rather than their expression influenced by the environment.