Why is there a great concern about the 'microbeads' that are released into environment?
- A.They are considered harmful to marine ecosystems.
- B.They are considered to cause skin cancer in children.
- C.They are small enough to be absorbed by crop plants in irrigated fields.
- D.They are often found to be used as food adulterants.
Correct answer
Explanation
The correct answer is A, They are considered harmful to marine ecosystems. Microbeads are tiny plastic particles that wash into rivers and seas, where they persist and are eaten by marine life.
Microbeads are solid plastic spheres, usually of polyethylene and smaller than 5 millimetres, once added to face scrubs, toothpastes and shower gels for their scrubbing action. They are too small to be caught by sewage treatment plants, so they flow into water bodies. Fish, plankton and shellfish mistake them for food, and the beads also absorb toxic chemicals from the water, which then move up the food chain. Because of this, the United States banned them in rinse-off cosmetics in 2015, and the Bureau of Indian Standards classified them as unsafe for use in cosmetic products in India.
B is wrong: there is no established link between microbeads and skin cancer in children.
C is wrong: the main concern is aquatic life, not uptake by crop roots.
D is wrong: microbeads are a cosmetic ingredient, not a food adulterant.
Exam tip: microbeads = primary microplastics (under 5 mm) from cosmetics; the worry is marine food chains.
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 →Which one of the following is NOT decomposed by bacterial action ?
- A.Vegetable remains
- B.Plastic materials
- C.Animal carcasses
- D.Wastes of flowers
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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.
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.
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