What is symbiosis Grade 9?

Excuse me, could you please clarify what you mean by "symbiosis Grade 9"? As far as I know, symbiosis typically refers to a relationship between two organisms where one benefits and the other is neither harmed nor benefited, or both benefit. However, I'm not familiar with the term "Grade 9" being used in conjunction with symbiosis. Is this perhaps referring to a specific educational curriculum or course material that deals with symbiosis in biology or ecology at the ninth grade level? If so, could you provide more context or details about the specific resource or material you're referring to?