All the plants and animals in an area area interdependent and interrelated to each other in their physical environment. What is the name given to this interrelationship and interdependence?

Question

$\begin{array}{1 1} (a)\; \text{physical environment } \\ (b)\; \text{ecosystem} \\ (c)\; \text{Biomes} \\ (d)\; \text{food chain} \end{array}$