Define symbiosis.

Symbiosis is defined as a close interaction between two different biological species, and this definition encompasses a range of relationships that can exist between organisms. This interaction can take various forms, including mutualism, commensalism, and parasitism. In mutualism, both species benefit, while in commensalism, one species benefits and the other is neither helped nor harmed. In parasitism, one species benefits at the expense of the other. The essence of symbiosis lies in the sustained interactions between different species, which can significantly influence their behavior, health, growth, and ecological roles. Therefore, this definition captures the complexity and the variety of relationships in nature that fall under the umbrella of symbiotic interactions.