changed in order to improve or made more fit for a particular purpose; "seeds precisely adapted to the area"; "instructions altered to suit the children's different ages"

When something is changed to help it do a particular thing. When the shape of a cell helps it do its job it is said to be 'adapted' to its job.

adjusted to a situation

Changed to fit into a new environment or situation.

The past tense of the process of adaptation - something has already changed to make the organism better suited to the environment it lives in.