My best guess would be c because b makes no since we as humans do not have photosynthesis and are considered living organisims, d is also wrong because the brain requires oxygen, and its not a because the brain is made of cells.
A symbiosis is an evolved interaction or close living relationship between organisms from different species, usually with benefits to one or both of the individuals involved.
Smaller animals and or animals that eat vegetation.
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The correct answer is True , my reason being is because they eat decomposed / decomposing things to get their food, they are not fighters , rather lazy