The ability of an organism to change internally or externally in relation to its environment is called adaptation.

Here's why:

* Adaptation refers to the process by which organisms evolve over time to become better suited to their environment. This can involve changes in their physical characteristics (external), internal functions (internal), or behaviors.

Examples of adaptation:

* External: A desert fox having large ears to dissipate heat.

* Internal: A fish developing a system to filter salt from its blood in a saltwater environment.

* Behavioral: Birds migrating to warmer regions during winter.

Let me know if you have any other questions!