Which one of the following is NOT decomposed by bacterial action ?
- A.Vegetable remains
- B.Plastic materials
- C.Animal carcasses
- D.Wastes of flowers
Correct answer
Explanation
The correct answer is B, Plastic materials. Ordinary plastics are non-biodegradable, so bacteria and fungi cannot break them down in any useful length of time.
Most plastics, such as polyethylene, polypropylene and PVC, are long synthetic polymers made from petroleum. Microbes in nature have no common enzymes to cut these strong carbon chains, so a plastic bag or bottle can stay in soil or water for hundreds of years, slowly breaking into microplastics instead of rotting. This is why plastic waste must be reduced, reused or recycled rather than left to decompose. Materials that come from living things are biodegradable because decomposers can digest them and return their nutrients to the soil.
A is wrong because vegetable peels and remains are plant matter that rots quickly and makes good compost. C is wrong because dead animals are broken down by bacteria, fungi and scavengers. D is wrong because flower waste is organic and decomposes easily.
Exam tip: biodegradable = from living things (food, paper, dung); non-biodegradable = plastic, glass, DDT, aluminium cans.
Practice Questions
View allWhich of the following is/are renewable source(s) of energy? 1. Fossil fuel 2. Biofuel 3. Uranium 4. Hydropower Select the correct answer using the code given below.
- A.2 only
- B.3 and 4
- C.1 and 3
- D.2 and 4
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Biofuel and hydropower are renewable because nature replaces them within a human lifetime, while fossil fuels and uranium are not.
Read the full explanation →According to the Environmental Protection Agency (EPA), which one of the following is the largest source of sulphur dioxide emissions?
- A.Locomotives using fossil fuels
- B.Ships using fossil fuels
- C.Extraction of metals from ores
- D.Power plants using fossil fuels
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The EPA names the burning of fossil fuels by power plants and other industrial facilities as the largest source of sulphur dioxide.
Read the full explanation →Free swimming macroscopic animals in an aquatic environment are referred to as
- A.Plankton
- B.Periphyton
- C.Benthos
- D.Nekton
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Nekton are animals large enough to be seen with the naked eye that swim actively and can move against water currents.
Read the full explanation →Artificial way of causing rainfall to reduce air pollution makes use of
- A.silver iodide and potassium iodide
- B.silver nitrate and potassium iodide
- C.silver iodide and potassium nitrate
- D.silver nitrate and potassium chloride
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These salts are the usual seeding agents in cloud seeding, the artificial way to make rain. Cloud seeding sprays tiny particles into clouds that already hold moisture, from aircraft, rockets or ground generators.
Read the full explanation →As per the Solid Waste Management Rules, 2016 in India, which one of the following statements is correct?
- A.Waste generator has to segregate waste into five categories.
- B.The Rules are applicable to notified urban local bodies, notified towns and all industrial townships only.
- C.The Rules provide for exact and elaborate criteria for the identification of sites for landfills and waste processing facilities.
- D.It is mandatory on the part of waste generator that the waste generated in one district cannot be moved to another district.
Show answer
The 2016 Rules set out detailed criteria for choosing sites for landfills and waste processing facilities. The Solid Waste Management Rules, 2016, framed under the Environment (Protection) Act, 1986, replaced the Municipal Solid Wastes Rules of 2000.
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