How are algae and polyps related

The polyps embed themselves in the flesh of the algae.
The polyps receive shelter from the algae.
The polyps receive carbon dioxide from the algae.
The polyps get most of their food from the algae.

Algae and polyps have a mutualistic relationship where the polyps receive most of their food from the algae. The algae provide nutrients and energy through photosynthesis, which the polyps then consume. This symbiotic relationship benefits both organisms involved.