Step-by-step explanation:
Remember that a biome is the set of ecosystems of a biogeographic zone. Thus, the biomes are areas that have similar climates, plant and animal populations, and share geographic conditions. Now, an ecosystem consists of all the biotic and abiotic factors in an area and their interactions. Thus, ecosystems can vary in size and that means ecosystems can be very tiny or very large.
This means that the correct answer is:
Answer:
D. Ecosystems are always smaller than a biome.