Answer: Fat-soluble and not readily broken down, so they accumulate at progressively higher concentrations in higher trophic levels.
- A Water-soluble and excreted rapidly, so they show no net accumulation at any trophic level according to most studies in the majority of documented cases
- B Equally concentrated at every trophic level, since dilution offsets any accumulation under most conditions studied in most observed cases
- C Broken down quickly by decomposers before reaching herbivores in the food chain as widely reported in standard reference material
- D Fat-soluble and not readily broken down, so they accumulate at progressively higher concentrations in higher trophic levels
Correct answer: D. Fat-soluble and not readily broken down, so they accumulate at progressively higher concentrations in higher trophic levels
Explanation: Persistent, fat-soluble pollutants like DDT are not efficiently excreted or metabolized; they accumulate in fatty tissues and become increasingly concentrated at each successive trophic level, a process called biomagnification.
Sunlight passes through the atmosphere and warms the surface; the surface re-radiates this energy as infrared heat, which greenhouse gases (CO₂, CH₄, water vapour) absorb and trap - a naturally beneficial process that intensifies into global warming as gas concentrations rise from human activity.
Concept context
Pollution, global warming, ozone depletion, deforestation, and sustainability. Important for NEET and general awareness.