Question

The terrestrial and aquatic ecosystems can be differentiated on the basis of the fact that
A. Organisms in terrestrial ecosystems are dependent on oxygen, while those in aquatic ecosystems are not
B. Nutrients are a limiting factor for populations in aquatic ecosystems but not for terrestrial populations.
C. Producers make up the greatest amount of biomass in terrestrial ecosystems, while in aquatic ecosystems they do not.
D. Sunlight is a limiting factor for populations in terrestrial ecosystems but not for populations in aquatic ecosystems.
E. Energy in the aquatic ecosystem is transferred from lower to higher trophic levels, but it moves in the opposite direction in aquatic ecosystems.

Answer 1

Hint: A terrestrial ecosystem is a community of land-based organisms having an interaction of biotic and abiotic components in an area. An aquatic ecosystem is an ecosystem existing in water bodies which include lakes, rivers, oceans, and streams, etc.

Complete answer: In the terrestrial ecosystem, the producers are represented by the green plants which provide the energy and nutrients to the other organisms of the higher level in a food chain. Whereas in aquatic ecosystems, the primary producers are represented by bacteria, phytoplankton, and algae which prepare food or act as a source of food for consumers. The pyramid of biomass in the terrestrial ecosystem is always upright as the biomass decreases from producers to primary and secondary consumers. This means that the producers are more in amount. The pyramid of biomass in the aquatic ecosystem is inverted as the number of producers (phytoplankton) is less than the consumers (zooplankton, fishes). This means the producers are less in amount. Also, the organisms of both terrestrial and aquatic ecosystems are dependent on oxygen. In the terrestrial ecosystem, the availability of nutrients is limited as compared to that of the aquatic ecosystem. In the aquatic ecosystem, the sunlight is not able to reach in depth thus acting as a limiting factor.
Therefore, the correct answer is option C.

Note: The producers in terrestrial ecosystems comprise plants and autotrophs. The biomass of producers are more compared to consumers as they are more in number. In the case of the aquatic ecosystem, the producers (phytoplankton) are less in biomass and consumers are more in biomass.