Among the options provided, which one is not recognized as a functional unit within an ecosystem?

Stratification

The correct answer is Option (4) -Stratification

(1) Energy flow: Energy flow refers to the transfer and transformation of energy within an ecosystem. It is a fundamental process that drives the movement of energy from producers (plants) to consumers (animals) through different trophic levels. Energy flow is essential for sustaining the biological activities and functioning of an ecosystem.

(2) Decomposition: Decomposition is a crucial process in ecosystems where organic matter, such as dead plants and animals, is broken down and recycled by decomposers, such as bacteria, fungi, and detritivores. Decomposition helps release nutrients back into the ecosystem, making them available for other organisms. It plays a vital role in nutrient cycling and ecosystem functioning.

(3) Productivity: Productivity refers to the rate at which organic matter, such as biomass or energy, is produced by autotrophic organisms (primarily plants) through photosynthesis. It is an important measure of the ecosystem's ability to support and sustain life. High productivity indicates a greater availability of resources for organisms within the ecosystem.

(4) Stratification: Stratification refers to the layering or division of different ecological zones within an ecosystem, particularly in aquatic or terrestrial habitats. It involves the vertical division of habitats based on factors such as light penetration, temperature, and nutrient availability. Stratification can lead to the formation of distinct ecological zones, each with its own set of physical and biological characteristics.

Now, let's identify the option that is not considered a functional unit within an ecosystem:

The correct answer is (4) Stratification. While stratification is a phenomenon that can occur within ecosystems, it is not typically considered a functional unit. Functional units refer to specific processes or components that contribute to the functioning and dynamics of an ecosystem, such as energy flow, decomposition, and productivity. Stratification, on the other hand, describes a spatial organization within an ecosystem rather than a functional process.