Final answer:
The intertidal zone is the environment that most favors the evolution of phenotypic plasticity due to its highly variable conditions, leading to selective pressures that require organisms to adapt to changing moisture, temperature, and salinity.
Step-by-step explanation:
The environment that favors the evolution of phenotypic plasticity is one that presents a variety of changing physical conditions requiring organisms to adapt dynamically to survive. The intertidal zone is an example of such an environment. Organisms in this zone must be capable of withstanding drastic changes in moisture, temperature, and salinity as they are exposed to air during low tide and submerged during high tide. The constantly changing conditions promote the development of phenotypic plasticity as a survival mechanism to these often harsh and variable conditions.
Conversely, environments like the deep ocean (abyssal), desert, and tropical rainforest (tropical wet forest) may be less variable on a short-term basis or may select for different types of adaptations, but the intertidal zone, with its dynamic abiotic challenges, is particularly conducive to promoting phenotypic plasticity.