The correct option is A A - T, B - T, C - T, D - T
Ecosystem is the functional unit of nature. It is a self-sustaining and self-regulating unit formed due to the interaction of both the biotic (living) and abiotic components (non-living).
All living organisms present in an ecosystem are known as biotic components. They include producers, consumers and decomposers (fungi and bacteria). Biotic components depend on abiotic components for their existence.
Non-living components of the ecosystem are known as abiotic components. It includes various factors like the temperature, air, humidity, salinity, sunlight, pH, etc present in the ecosystem.
Hence, A and B are true.
Abiotic components are present in the lithosphere (the rocky outer part of the Earth), hydrosphere (the total amount of water on a planet) and atmosphere (layers of gases that envelope Earth).
Hence, C is true.
The interaction of biotic and abiotic components results in the physical structure characteristic for each ecosystem. For example, in tropical rain forests there is vertical distribution of plants at different levels. The trees occupy the top vertical strata or layer of a forest, shrubs occupy the second layer and herbs and grasses occupy the bottom layers.
Hence, D is true.