State Hooke's law.

Explanation

Statement: The ratio of stress to strain is a constant for a material with in the elastic limit.
Modulus of elasticity `=("Stess")/("Strain")`

Within the elastic limit, stress v/s strain is a straight line A is the elastic limit upto which Hooke's law is applicable. Beyond B the yielding point, the wire extends but does not return to the initial state when the deforming force is remoed. F is the breaking point.
EF allows the material to be malleable and DE, ductile.