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Ecosystems — BIOLOGY STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 ScienceBIOLOGYEcosystems5 Marks
Question

The above diagram shows a simplified biogeochemical cycle.

  1. Name the compound whose cycle is depicted.
  2. In what way do vehicles add this compound to atmosphere?
  3. What adverse effect does its excess have on the environment?
  4. Cite an event which depicts this effect in the modern times.
  5. Suggest two ways of reducing this effect.
✓

Answer

  1. Carbon dioxide.
  2. Burning of fossil fuels-petrol/ diesel, in the vehicle produces carbon dioxide.
  3. Carbon dioxide is a green house gas and absorbs the infrared radiation emitted by the earth; this results in an increased mean temperature of the atmosphere, also called global warming.
  4. Melting of ice caps.
  5. Measures to reduce global warming include:
  • Reducing the use of fossil fuels to reduce emission of greenhouse gases.
  • Reducing deforestation and planting more trees.

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