Science [3 Mark Questions]

Wastes which are generated in our house daily and measures for their disposal are as follows:

• Raw vegetable and peels of fruits: Can be disposed underground in a nearby garden which on decomposition enriches the soil with nutrients.
• Paper wastes like newspaper, books etc: Can be recycled or can also be sold.
• Plastic waste like polybags, plastic toys etc: Can be sold in suitable shops where they can be recycled.
• Other household waste like pieces of glass, clothes etc: Should be safely dumped in garbage bins placed to collect non-biodegradable waste.

The flow of energy in the ecosystem is unidirectional. The energy enters the plants(from the sun) through photosynthesis during the making of food. This energy is then passed on from one organism to another in a food chain.Energy given out by the organisms as heat is lost to the environment, it does not return to be used by the plants again. This makes the flow of energy in ecosystem 'unidirectional'. Thus, the flow of energy in the ecosystem is said to be unidirectional because the energy lost as heat from the living organisms of a food chain cannot be reused by plants in photosynthesis.
The flow of energy is generally from
Sun --> Producer → Primary Consumer → Secondary Consumer → Tertiary Consumer.
since the flow of energy is progressiely from one trophic level to another and does not revert back, it is siad to be unidirectional. Further, the available energy decreases in the higher trophic levels making it impossible for energy to flow in the reverse direction.