Answer:
B. Organisms in each ecological system have evolved in that system and have adaptations suited for that environment.
Step-by-step explanation:
Every organism lives in a habitat, within which it lives in an ecosystem best suited for its need. An organism needs food, water and a favorable weather to live. For an organism to survive in an ecosystem, it needs to adapt to the conditions in that ecosystem, else it dies. Therefore, different types of organisms in different systems will have varying characteristics.
This is linked to Charles Darwin’s theory of evolution which implies that all organism in an ecological system evolve heritable traits suited for their environment.