Answer:
RubisCO.
Explanation: RubisCO which is an enzyme with the chemical formular
Ribulose-1,5-bisphosphate carboxylase/oxygenase,it is the most abundant usually referred to as the most abundant Enzyme and protein molecule in the universe,its Activities cut across everywhere photosynthesis takes place,it helps to fix atmospheric carbon dioxide in the green plants during photosynthesis leading to the production of glucose etc.