Final answer:
A niche is the role a species plays in its ecosystem, encompassing all interactions with biotic and abiotic factors including sources of energy, nutrient cycling, and relationships with other organisms. The correct answer is 'C. All of the resources a species uses within its ecosystem'.
Step-by-step explanation:
A niche in ecology refers to the role of a species within its ecosystem. Not to be confused with its habitat, which is the physical space a species occupies, a niche includes all the interactions a species has with both the biotic and abiotic components of its environment. This encompasses the way a species gets its energy and nutrients, how it contributes to the flow of energy in the ecosystem, its interactions with other organisms, its role in recycling nutrients, and any other factors contributing to its way of life within the ecosystem. For example, the jumping spider has a niche as a carnivore that obtains its food by preying on insects like flies.
Therefore, according to the provided options, the correct answer is C. All of the resources a species uses within its ecosystem. This definition encapsulates the multifaceted interactions and roles the species plays in its environment.