Which of the following plants has stipules modified into spines?
Parkinsonia
Zizyphus
Acacia
All of these
Parkinsonia, Zizyphus, and Acacia are three plants that can have their stipules transformed into spines.
Stipules are little leaf-like structures found near the base of some plants' leaves. Stipules in certain plant species can undergo changes and turn into spines. These spines serve a variety of functions, including defense against herbivores, water conservation, and structural support.
Plants that can have their stipules converted into spines include Parkinsonia, Zizyphus, and Acacia. These modifications allow them to survive in certain environmental circumstances while also protecting them from grazing animals and other potential predators.
Hence, option 4 is the correct answer.