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NCERT Solutions for Class 10th Science


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Chapter 15. Our Environment

Chapter Review




Chapter Review:

  • Substances that are broken down by the biological processes are said to be biodegradable.
  • Substances that are not broken down by biological processes are said to be non-biodegradable.
  • Ecosystem is a structural and functional unit of the biosphere consisting of a community of living beings and the physical environment; both interacting exchanging materials between them.
  • The abiotic component of an ecosystem is a community of Physical environment.
  • The biotic component of an ecosystem is a community of living organisms.
  • These are the organisms which are able to systhesise their food. They are mainly green plants.Therefore, all green plants are called producers. They are also called autotrophs.
  • They are organisms which consume other organisms or their products as their food. The consumers depend upon producers for their food directly or indirectly. They get their food either by eating other organisms or their products.
  • These are organisms (animals) which get their food by eating the
    producers (or plants) directly. Herbivores are also called first order
  • These are organisms (animals) which consume other animals.
    Therefore, carnivores feed on the flesh of harbivores. These are also called primary carnivores or second order consumers.
  • The organisms which feed on both plants and animals are called
  • Which break down the complex organic compounds present in dead organisms like plants and their products into a simpler substance. These are called reducers.
  • The network of various food chains which are interconnected at various tropic levels is called food web.
  • One organism consumes another organism to transfer food energy is called a food chain. In a food chain, unidirectional transfer of energy takes place.
  • Energy is used and conveyed from one trophic level to another is a food chain. This is called flow of energy.
  • According to ten percent law only ten percent of the energy entering a particular trophic level is stored and the remaining is lost during energy transfer.
  • Chemicals like DDT are widely used to kill pests.


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