The use of plastics has led to a number of environment-related problems. For this, which one of the following statements is correct?
- A.They are non-biodegradable.
- B.They do not get released into water and food.
- C.They do not have any biochemical synthesis activity.
- D.They are harmless to humans.
Correct answer
Explanation
The correct answer is A, They are non-biodegradable. Bacteria and fungi cannot break down most plastics, so plastic waste stays in soil and water for hundreds of years.
Common plastics such as polythene, PVC and PET are long-chain polymers made from petroleum. Microbes lack the enzymes to digest these chains, so the waste only breaks into smaller pieces called microplastics. It clogs drains, harms animals that swallow it, and releases toxic gases such as dioxins when burnt.
B is wrong because microplastics and chemical additives do get into water, salt, seafood and other food.
C is wrong because the statement is not the reason for the pollution problem; the problem comes from plastics persisting, not from any synthesis activity.
D is wrong because plastic additives such as BPA and phthalates, and smoke from burning plastic, can harm human health.
Exam tip: biodegradable waste is broken down by microbes; plastic, glass and metal cans are non-biodegradable.
Practice Questions
View allWhich one of the following statements with regard to growth of coral reefs is not correct?
- A.Coral can grow abundantly in freshwater.
- B.It requires warm water between 23 °C-25 °C.
- C.It requires shallow saltwater, not deeper than 50 metres.
- D.It requires plenty of sunlight to aid photosynthesis.
Show answer
Reef-building corals are marine animals and die in fresh water, so this statement is false. Corals are tiny polyps that build skeletons of calcium carbonate and live with algae called zooxanthellae inside their tissues.
Read the full explanation →Which one of the following biosphere reserves is spread over three States in India?
- A.Nilgiri
- B.Achanakmar-Amarkantak
- C.Seshachalam
- D.Agasthyamalai
Show answer
The Nilgiri Biosphere Reserve spreads across Tamil Nadu, Kerala and Karnataka. Set up in 1986, Nilgiri was India's first biosphere reserve, and in 2000 it became the first Indian reserve on UNESCO's World Network of Biosphere Reserves.
Read the full explanation →Which 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
Show answer
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
Show answer
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
Show answer
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 →