In an ecosystem

The correct answer is Option (2) → Energy flows and nutrients cycle

In an ecosystem: Energy flows and nutrients cycle

Energy flows in one direction, from the sun to producers and then through various trophic levels, eventually being lost as heat. In contrast, nutrients (such as carbon, nitrogen, and phosphorus) are recycled within the ecosystem, moving through the biotic and abiotic components in a continuous cycle. Nutrients which are never lost from the ecosystems, rather they are recycled time and again indefinitely. The movement of nutrient elements through the various components of an ecosystem is called nutrient cycling.

So, the correct answer is: Energy flows and nutrients cycle