Answer: The correct answer is -
Symbiosis.
Explanation:
Symbiosis can be described as close biological interaction between two organisms belonging to the same or different species. There are different types of symbiotic relationships such as mutualisms, parasitism, and commensalism.
Example - lichen represents mutualistic relationship between photosynthetic organism such as algae and a fungus.
Thus, symbiosis is the right answer.
