RuBisco is an enzyme required for photosynthesis in which of the following
I) Chlorella 
II) Sugarcane
II) Tomato 
IV) Opuntia

RuBisco (Ribulose-1,5-bisphosphate carboxylase/oxygenase) is a key enzyme in the process of photosynthesis, responsible for fixing carbon dioxide into organic molecules. It is present in all photosynthetic organisms, including algae, plants, and cyanobacteria.

Chlorella is a type of unicellular green algae that undergoes photosynthesis and requires RuBisco to fix carbon dioxide. Similarly, sugarcane, tomato, and Opuntia (a type of cactus) are all plants that undergo photosynthesis and require RuBisco for carbon fixation.