Answer:
Bacteria
Explanation:
You have isolated a microorganism that is green, photosynthetic, has a cell wall, and does not possess a nucleus. This organism is a bacteria.
Bacteria such as cyanobacteria are photosynthetic and generally bacteria are classified as prokaryotes, that is the lack a nucleus and they have cell walls. The cell wall of bacteria is usually the target of antibiotics in the treatment of bacteria infections.
