કારણ : સ્થિતિસ્થાપક રબરમાં પ્લાસ્ટિક ગુણ વધારે હોય.
If strain changes stress also changes since \(Y\) is constant for a material.
Also, poisson's ratio \(=\frac{\text { lateralstrain }}{\text { longitudinalstrain }}\)
\(\nu=0.5\) for rubber and is most elastic material.
So, both are correct but not reason of assertion.