The correct option is (d) 1, 2, 3 and 4.
Explanation
Ecosystem imbalance is primarily caused by anthropogenic activities that disrupt the natural interactions between biotic (living) and abiotic (non-living) components. These disruptions degrade habitats, reduce biodiversity, and alter ecological cycles.
Statement-wise Analysis:
- Statement 1 is Correct: Hunting for commercial purposes (poaching) results in the rapid decline or extinction of specific animal species. This removal of key species disrupts food chains and population dynamics, leading to ecological instability.
- Statement 2 is Correct: Pollution caused by chemical and industrial waste introduces toxins into the air, water, and soil. This degrades the quality of natural habitats, harms wildlife physiology, and alters the chemical balance required for the survival of flora and fauna.
- Statement 3 is Correct: The introduction of alien (invasive) species into new environments often leads to a decline in native biodiversity. These species may lack natural predators and outcompete indigenous species for resources, causing imbalances in the local ecosystem.
- Statement 4 is Correct: Reckless cutting of forests (deforestation) for cultivation, habitation, or industry destroys natural habitats. It leads to soil erosion, loss of carbon sinks, and disruption of the water cycle, which are fundamental to ecosystem stability.
Key Takeaway:
The major threats to nature and causes of ecosystem imbalance include habitat destruction (deforestation), overexploitation of resources (hunting), environmental pollution, and the introduction of invasive alien species.