Thorns and spines are analogous organs. Analogous organs are those which have different function but have similar look and structure.
Thorns are basically modified stem and spines are modified leaves. Both the thorns and spines are different in structure but they have same function which are as follows -
The correct option is ANALOGOUS STRUCTURES. Analogous structures are structures that are similar because of the functions they carry out and because of their external appearance. But these structures are different internally.<span />