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The biomass available for consumption by the herbivores the decomposers is called

  • net primary productivity

  • secondary productivity

  • standing crop

  • standing crop


A.

net primary productivity

Net Primary productivity (NPP) is the weight of organic matter stored by producers in a unit area/ volume per unit time.NPP is equal to the rate of organic matter created by photosynthesis minus the rate of respiration and other loses. Stored biomass is transferred from one trophic level to another trophic level. Secondary productivity is the rate of energy storage at consumers levels-herbivores, carnivorous and decomposers. 

Gross Primary productivity (GPP) is referred as total rate of photosynthesis including the organic matter used up in respiration during the measurement period.

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The breakdown of detritus into smaller particles by earthworm is a process called 

  • humification 

  • fragmentation

  • mineralisation

  • mineralisation


Which domestic sewage mixes with river water

  • small animals like rats will die after drinking river water

  • the increased microbial activity releases micronutrients such as iron

  • the increased microbial activity uses up dissolved oxygen

  • the increased microbial activity uses up dissolved oxygen


An imporved variety of trasgenic basmati rice

  • does not require chemical fertilisers and growth hormones

  • gives high yield nd is rich in vitamin-A

  • is completely resistant to all insect pests and diseases of paddy

  • is completely resistant to all insect pests and diseases of paddy


Study the four statements (1-4) given below and select the two correct one out of them.
1. A lion eating a deer and a sparrow feeding on grain are ecologically similar in being consumers
2.Predator starfish pisaster helps in maintaining species diversity of some invertebrates
3.Predators ultimately lead to the extinction of prey species
4.Production of chemicals such as nicotine, strychnine by the plants are metabolic disorders
The two correct statements are 

  • (2) and (3)

  • (3) and (4)

  • (1) and (4)

  • (1) and (4)


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