The correct answer is C. Birds eating seeds from plants.
Step-by-step explanation
An ecosystem is a set of species in an area that interact with each other and with their abiotic environment. In this, the organisms interact in an intraspecific way, that is, between organisms of the same species, generally oriented towards obtaining food and defending the species against environmental hazards (cold, heat, predators, among others) for example lions when hunting in groups. On the other hand, there are interspecific interactions (elements of different species) are important as they favor the structuring of the system, for example, birds eating seeds of plants. So, the correct answer is C. Birds eating seeds from plants.