Answer:
The correct answer is : parasitism.
Explanation:
Parasitism is a symbiosis relationship in which two organism lives together but only one is benefited and other harm in any means. Toxoplasma is, in this case, parasite which is benefited while cats are host and harmed in this relationship.
Degree and chances of harm or benefit do not defines the symbiosis relationship between two organism. Cats are rarely harmed but still harmed in this relationship.
Thus, the correct answer is : parasitism.
The coral provides the algae with a protected safe environment (a home) and compounds they need for photosynthesis. The algae in return, produce oxygen and help the coral to remove wastes. Most importantly, zooxanthellae supply the coral with glucose, glycerol, and amino acids, which are the products of photosynthesis.
Could you ask again but with more details? I do not understand.
Http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0072434/
There is a website with some info. Hope it helps! :)