Final answer:
Eukaryotic green algae and higher plants share the common metabolic process of photosynthesis, where they use sunlight to convert carbon dioxide and water into glucose and oxygen.
Step-by-step explanation:
The metabolic process that all eukaryotic green algae and higher plants have in common is photosynthesis. Eukaryotes, such as green algae and higher plants, are able to perform photosynthesis, which involves capturing the energy of sunlight to convert carbon dioxide and water into glucose, releasing oxygen as a byproduct. This process takes place in the chloroplasts, an organelle found in these photosynthetic organisms. While glycolysis, transcription, and translation are other fundamental metabolic processes found in all living organisms, not all eukaryotes perform photosynthesis. Thus, considering the similarities between green algae and higher plants, photosynthesis is the unique commonality.