Leaves are reduced to spines in Opuntia. This is an example of

Adaptations are result of natural selection that leads to variations in living organisms due to mutation and recombination. Adaptations may be behavioural, morphological and/ or physiological which enable an organism to survive and reproduce in its habitat. In some desert plants like Opuntia, leaves are reduced to spines and the photosynthetic function is taken over by the flattened stems. This is a morphological adaptation.