Context: Some symbiotic relationships are obligate, meaning that both symbionts entirely depend on each other for survival. For example, many lichens consist of fungal and photosynthetic symbionts that cannot live on their own. Others are facultative (optional): they can, but do not have to live with the other organism.

Question: What is the type of symbiotic relationship where two organisms can't survive without each other?
Answer: obligate

Question: What is the type of symbiotic relationship where the symbionts can live together but can also survive alone?
Answer: facultative

Question: What is an example of an obligate relationship?
Answer: lichens

Question: What is the type of symbiotic relationship where two organisms can survive without photosynthetic symbionts?
Answer: Unanswerable

Question: What organism demonstrates only the facultative symbiotic relationship?
Answer: Unanswerable

Question: What organism demonstrates only the obligate symbiotic relationship?
Answer: Unanswerable

Question: What is the type of symbiotic relationship where two organisms can survive without fungal symbionts?
Answer: Unanswerable

Question: What is the type of symbiotic relationship where many organisms must depend on photosynthetic symbionts?
Answer: Unanswerable