Trophic levels, biomagnification, ozonePractice Questions & MCQs

Q1. Which of the following statements about the ozone layer is INCORRECT?

• A.It is found mainly in the troposphere where it filters most of the harmful UV radiation
• B.It is mainly found in the stratosphere
• C.It absorbs harmful ultraviolet radiation
• D.Chlorofluorocarbons released from refrigerants and aerosols damage it

Answer: A. It is found mainly in the troposphere where it filters most of the harmful UV radiation

The core fact here is - The first option is INCORRECT - the protective ozone layer is in the STRATOSPHERE, not the troposphere. Tropospheric ozone is in fact a pollutant. The other three options are correct: stratospheric location, UV-absorbing function and CFC-mediated destruction. Hence the answer is A) It is found mainly in the troposphere where it filters most of the harmful UV radiation.

Q2. Which of the following is the BEST sequence of biological waste-treatment options ranked from MOST environmentally preferable to LEAST?

• A.Reduce → Reuse → Recycle → Incinerate → Landfill
• B.Landfill → Incinerate → Recycle → Reuse → Reduce
• C.Recycle → Reuse → Reduce → Landfill → Incinerate
• D.Incinerate → Landfill → Reduce → Reuse → Recycle

Answer: A. Reduce → Reuse → Recycle → Incinerate → Landfill

That leaves only option A). Confirm with the chapter rule: The waste hierarchy ranks 'reduce' (don't create the waste) as the best option, then 'reuse' (use the same item again without processing), then 'recycle' (reprocess into new products). Incineration and landfill are last-resort disposal options because they generate emissions or occupy land. Reversing the order would put the most polluting strategies first, which is environmentally wrong (biology, chapter 'Our Environment'). Answer: A) Reduce → Reuse → Recycle → Incinerate → Landfill.

Q3. Which of the following is INCORRECT about the 10% law of energy transfer in ecosystems?

• A.It implies that energy can be efficiently transferred between any two trophic levels with no loss
• B.It was proposed by Lindemann
• C.About 90% of the energy is lost as heat or used in metabolism at each transfer
• D.It explains why food chains rarely have more than 4-5 trophic levels

Answer: A. It implies that energy can be efficiently transferred between any two trophic levels with no loss

That leaves only option A). Confirm with the chapter rule: The first option is INCORRECT - the very meaning of the 10% law is that energy is HEAVILY lost (about 90%) at each transfer, not efficiently transferred. The other three options correctly describe Lindemann's law, the loss as heat/metabolism and the natural limit on food-chain length (biology, chapter 'Our Environment'). Answer: A) It implies that energy can be efficiently transferred between any two trophic levels with no loss.