CIE Biology Paper-4: Specimen Questions with Answers 20 - 22 of 120

Question number: 20

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Habitats are destroyed when we use land for other purposes. Explain it

Explanation

Habitat destruction is the main cause of threatening the different species because each species has adaptations to survive in a particular environment. If we destroy their habitat, and then it will difficult for many species to survive in new kind of environment. Examples of habitat destruction are-

  • Cut off native vegetation for growing crops, farming livestock, build houses and factories.
  • We damage habitats when mining process are done
  • Due to pollutions

Question number: 21

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What do you mean by eutrophication in water?

Explanation

Eutrophication arises from the oversupply of nutrients in water bodies. When many nutrients, like nitrogen and phosphorous, are present, usually because of runoff from the surrounding land that is called as a eutrophic stream. Eutrophication is mainly the result of human activity.

Farms, lawns and other fields tend to be heavily fertilized by people. These fertilizers are the perfect type of nutrients to feed hungry algae and plankton, and when it rains, these fertilizers run off into lakes, streams, rivers and oceans and make the water nutrients rich.

Question number: 22

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What will be the result when a cross between two heterozygous tall pea plants occur?

Explanation

It shows how a single gene is passed on from parents to next generation. In addition, its ratio will be 3: 1

 Image shows cross between two heterozygous tall pea plants

Image Shows Cross between Two Heterozygous Tall Pea Plants

Image shows cross between two heterozygous tall pea plants (3: 1)