Limiting Factors & Ecosystem Cycles — NEET Biology

Which of the following statements regarding energy flow in an ecosystem are correct? S1: Photosynthetically active radiation (PAR) constitutes less than 50% of the incident solar radiation, and plants capture approximately 2-10% of this PAR. S2: Net Primary Productivity (NPP) represents the rate of production of organic matter during photosynthesis and is entirely available for consumption by heterotrophs. S3: The number of trophic levels is generally restricted because only about 10% of the energy from a lower trophic level is transferred to the next higher trophic level. S4: Ecosystems do not conform to the Second Law of Thermodynamics, as they maintain highly ordered structures through constant energy input. S5: In a terrestrial ecosystem, the grazing food chain (GFC) is typically the major conduit for energy flow, unlike in aquatic ecosystems where the detritus food chain (DFC) dominates. S6: Energy flow in an ecosystem is unidirectional, beginning with producers and eventually dissipating as heat to the environment.