Heterophyllous development in response to environment is an example of which of the following phenomena ?

The correct answer is Plasticity.

Heterophyllous development refers to the phenomenon where a plant produces leaves of different shapes or forms depending on the environmental conditions in which it grows. This ability to alter its morphology in response to external factors demonstrates that the organism can adjust its phenotype without changes to its underlying genetic code.

In biology, phenotypic plasticity (or simply plasticity) is defined as the capacity of an organism to change its observable traits—such as structure, physiology, or behavior—in response to varying environmental influences. This is a reversible and adaptive process that enables the organism to survive and thrive under different conditions.

Let's consider the other options to see why they are not appropriate:

Dedifferentiation is the process by which specialized, differentiated cells revert to a more primitive, less specialized state. Heterophyllous development does not involve cells losing their specialization; instead, it involves the formation of different leaf types while retaining their differentiated status.

Elasticity in a biological context usually describes the ability of a tissue or organ to return to its original shape after deformation. It does not describe changes in leaf form induced by environmental cues.

Redifferentiation occurs when dedifferentiated cells later specialize again into a particular cell type. Again, heterophyllous development does not entail a loss and subsequent re‑gain of specialization.

Since heterophyllous development exemplifies the organism’s ability to modify its phenotype (leaf shape) in direct response to environmental factors, it best matches the definition of plasticity.