Day-655 | Daily MCQs | UPSC Prelims | ENVIRONMENT AND ECOLOGY

Answer: A
Explanation:
Statement 1 is incorrect: The term ‘Deemed Forest’ has not been clearly defined in any law, including the Forest (Conservation) Act, 1980.
Such forests are notified neither with the forest department nor with the revenue department. These are such areas that are like forests but lack recognition in official or historical records. The Supreme Court in the case of T N Godavarman Thirumalpad (1996) accepted a wide definition of forests under the Act. “The word ‘forest’ must be understood according to its dictionary meaning. This description covers all statutorily recognised forests, whether designated as reserved, protected or otherwise for the purpose of Section 2 (1) of the Forest Conservation Act.
Statement 2 is correct: The apex court of the country in its 1996 judgement ordered the governments of states and Union Territories to identify and declare ‘deemed forests’ with the help of expert committees.
Statement 3 is incorrect: The deemed forests are a category of forest mentioned in the Odisha State Forest Act and the Madhya Pradesh’s state amendment to the Indian Forest Act.

Answer. C
Explanation: Invasive species are the alien species which when introduced into a foreign land threaten the survival of local/native species of flora/fauna since they tend to grow/reproduce at much faster pace, and outpace the native species by competing for resources (food, space, etc.).
The proliferation of invasive species has endangered various species of biodiversity in the country, which has become a matter of grave concern for environmentalists and policy-makers. Some of the invasive species which have been spreading and threatening flora and fauna in the Western Ghats and Central Indian Highlands include Senna spectabilis, Chromolaena odorata, Prosopis Juli fora, Lantana camara, Mikania micrantha, Xanthium strumarium, etc.
Senna spectabilis (Calceolaria shower), a species of the legume family, is native to South and Central America and is grown as an ornamental plant as it has bright yellow flowers. Introduced as shade trees for coffee and firewood in the country, it soon became a threat to native tree species as its dense foliage prevented the growth of other indigenous trees and grass species.
Chromolaena odorata is also known as Christmas bush, bitter bush, Siam weed, and baby tea. It is known to have originated from South and Central America.

Answer. C
Explanation:
Statement 1 is correct: Biochemical Oxygen Demand (BOD) is a measure of oxygen used by microorganisms such as bacteria to decompose the organic matter like sewage, dead plant leaves, grass blades and food wastes. If the amount of organic wastes is high in the water source, more bacteria will be present to consume oxygen. Under such polluted conditions demand for oxygen will be high and so the BOD values will be high. With high levels of BOD, levels of DO in the water decrease.
Statement 2 is correct: The BOD of a sample of water can be tested using a redox titration called the Winkler method. The principle of the Winkler method is as follows; oxygen in a water sample is made to oxidize iodide ions into iodine. The amount of iodine produced is determined by titrating with a standard thiosulphate solution. The amount of oxygen present in the original sample of water can be determined from the titre.

Answer. B
Explanation: Statements 1 and 2 are correct only.
The central government has been entrusted with the following powers and authority under the provisions of the Environment (Protection) Act, 1986, to:
● lay down standards for emission or discharge of environmental pollutants of air, water or soil for various areas and purposes;
● direct the closure, prohibition or regulation of any industry, operation or process;
● direct stoppage or regulation of the supply of electricity or water or any other service;
● establish or recognise environmental laboratories and institutes to carry out the functions entrusted to such environmental laboratories; etc.

Answer. A
Explanation:
Statement 1 is incorrect: Mustard is cultivated as a rabi crop in India. The yellow/white mustard is indigenous to Southern Europe whereas brown mustard is from China which was introduced to Northern India. The black mustard is endemic to the Southern Mediterranean region.
Statement 2 is correct: India has granted environmental clearance for indigenously developed genetically modified (GM) mustard seeds, paving the way for commercial use of its first GM food crop. The Genetically Engineering Appraisal Committee (GEAC), the country’s regulator for genetically modified organisms, recommended the “environmental release of mustard hybrid DMH-11 for its seed production and testing as per existing ICAR guidelines and other extant rules/regulations before commercial release.
Statement 3 is incorrect: By genetic modification (GM), the scientists at Delhi University’s Centre for Genetic Manipulation of Crop Plants (CGMCP) have developed the hybrid mustard DMH-11 containing two alien genes isolated from a soil bacterium called Bacillus amyloliquefaciens. It is a cross between the popular Indian mustard variety “Varuna” with an East European variety “Early Heera-2”. It is a herbicide resistant transgenic crop.