Correct Option
The correct option is (d) 1, 2 and 3.
Explanation
An ecosystem is composed of two main types of components: biotic and abiotic. Biotic components refer to all living organisms and the organic matter derived from them (living or once-living). Abiotic components refer to the non-living physical and chemical factors such as sunlight, temperature, water, soil, and air.
Statement-wise Analysis
- Statement 1 is Correct: Dead animals and dry leaves are organic matter derived from living organisms. In ecological classification, biotic components encompass not only currently living organisms but also their remains (detritus) and waste products, as these are of biological origin and distinct from inorganic abiotic factors like rocks or minerals.
- Statement 2 is Correct: Plants (producers) and animals (consumers) constitute the primary living populations within a forest ecosystem and are fundamental biotic components.
- Statement 3 is Correct: Microorganisms, such as bacteria and fungi, are living entities that act as decomposers. They play a critical role in breaking down organic matter and are classified as biotic components.
Key Takeaway
Biotic components include all living life forms (flora, fauna, microorganisms) and their organic by-products (dead remains), whereas abiotic components are the non-living physical elements of the environment.