Which of the following organisms has a symbiotic relationship with green algae?

The organism that has a symbiotic relationship with green algae is Hydra. Hydra is a freshwater organism that belongs to the phylum Cnidaria. It is a predatory animal that captures small aquatic animals with its tentacles. Hydra has a mutualistic symbiotic relationship with a species of green algae called Chlorella. Chlorella lives inside the cells of Hydra and provides it with food through photosynthesis. In return, Hydra provides Chlorella with a stable environment and protection from predation. The waste products of Chlorella also provide a source of nutrients for Hydra. This relationship between Hydra and Chlorella is an example of mutualism, a type of symbiosis in which both organisms benefit from the association.