"Biorock technology" is talked about in which one of the following situations ?
- A.Restoration of damaged coral reefs
- B.Development of building materials using plant residues
- C.Identification of areas for exploration/extraction of shale gas
- D.Providing salt licks for wild animals in forests/protected areas
Correct answer
Explanation
The correct answer is A, Restoration of damaged coral reefs. Biorock is a method of growing reef structures under the sea with a mild electric current, so that corals can settle and recover.
In this method a steel frame is placed on the sea floor and a safe, low-voltage direct current is passed through it. The current makes dissolved minerals in seawater, mainly calcium carbonate, deposit on the frame as a hard limestone coating, much like natural reef rock. Coral fragments fixed to the frame grow on this surface, and studies report that they grow faster and survive stress such as warm water better. The technique was developed in the 1970s and 1980s by the architect Wolf Hilbertz and the marine scientist Thomas Goreau, and it has been tried in India too, for example in the Gulf of Kachchh.
B is wrong because building materials from crop residues have nothing to do with biorock. C is wrong because shale gas exploration uses geological surveys, not biorock. D is wrong because salt licks are natural or artificial mineral deposits for animals and do not use this technique.
Exam tip: Biorock = mineral accretion by low-voltage current = coral reef restoration.
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 →