In human eye, cornea absorbs UV-B radiation, and a high dose of UV-B causes inflammation of cornea, called snow-blindness, cataract, etc. Such exposure may permanently damage the cornea. Answer : (d)

Earth Summit (Rio Summit)-1992, called upon all nations to take appropriate measures for conservation of biodiversity and sustainable utilisation of its benefits Answer : (b)

The Montreal Protocol sets binding progressive phase out obligations for developed and developing countries for all the major ozone depleting substances, including chlorofluorocarbons (CFCs), halons and less damaging transitional chemicals such as hydrochlorofluorocarbons (HCFCs).Adopted on 15 September 1987 Answer : (d)

Salmonella typhi is the causative agent. Confirmatory test = Widal test, it’s based on antigen antibody reaction. Answer : (d)

Storage of nuclear waste should be done in suitably shielded containers and buried within rocks deep below the earth's surface (500 m deep) Answer : (d)

In 1994, the United Nations General Assembly proclaimed 16 September the International Day for the Preservation of the Ozone Layer, commemorating the date of the signing, in 1987, of the Montreal Protocol on Substances that Deplete the Ozone Layer. Answer : (a)

Primary pollutants include ammonia, sulfur dioxide, nitrogen dioxide and carbon monoxide. Answer : (d)

There should be a balance between production and degradation of ozone in the stratosphere. Of late, the balance has been disrupted due to enhancement of ozone degradation by chlorofluorocarbons (CFCs). CFCs find wide use as refrigerants. CFCs discharged in the lower part of atmosphere move upward and reach stratosphere. In stratosphere, UV rays act on them releasing Cl atoms. Cl degrades ozone releasing molecular oxygen, with these atoms acting merely as catalysts; Cl atoms are not consumed in the reaction. Answer : (b)

Deforestation is conversion of forested area into non-forested area. Major reasons for deforestation are agricultutral expansion, overgrazing, wood and other products extraction. These factors are caused by living beings i.e., these are biotic factor. Answer : (c)

UV-B damages DNA and mutation may occur. It causes aging of skin, damage to skin cells and various types of skin cancers. In human eye, cornea absorbs UV-B radiation, and a high dose of UV-B causes inflammation of cornea, called snow-blindness, cataract, etc. Such exposure may permanently damage the cornea. Answer : (a)

Traditional rice production globally accounts for about 1.5% of greenhouse gas emissions, equivalent to all aviation emissions. Its source is methane, created by organic matter decomposing underwater in flooded paddies Answer : (b)

(a)In human eye, cornea absorbs UV-B radiation, and a high dose of UV-B causes inflammation of cornea, called snow-blindness, cataract, etc. Such exposure may permanently damage the cornea. (b)Eutrophication is the natural aging of a lake by nutrient enrichment of its water. (c)One of the major reasons of deforestation is the conversion of forest to agricultural land so as to feed the growing human population. Trees are axed for timber, firewood, cattle ranching and for several other purposes. Slash and burn agriculture, commonly called as Jhum cultivation in the north-eastern states of India, has also contributed to deforestation. (d)Sanitary landfills were adopted as the substitute for open-burning dumps. In a sanitary landfill, wastes are dumped in a depression or trench after compaction, and covered with dirt everyday. Answer : (a)

Recognising the deleterious affects of ozone depletion, an international treaty, known as the Montreal Protocol, was signed at Montreal (Canada) in 1987 (effective in 1989) to control the emission of ozone depleting substances. Answer : (d)

Plastic, glass junk and iron junk are physical pollutant and non-biodegradable which does not cause change in pH. Whereas detergents released from the domestic sewage, as well as the industrial effluents, result in the increasing the inorganic mineral quantity in the water body which changes pH of water bodies. Answer : (d)

Biomagnification is the build up of toxins in a food chain.DDT is stored in the fat of animals and takes many years to break down, and as the fat is consumed by predators, the amounts of DDT biomagnify. Photochemical smog, often referred to as "summer smog", is the chemical reaction of sunlight, nitrogen oxides and volatile organic compounds in the atmosphere, which leaves airborne particles and ground-level ozone.primary pollutants include nitrogen oxides, particularly nitric oxide (NO) and nitrogen dioxide (NO2), and volatile organic compounds. The relevant secondary pollutants include peroxylacyl nitrates (PAN), tropospheric ozone, and aldehydes. Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain. Global warming occurs when carbon dioxide (CO2) and other air pollutants and greenhouse gases collect in the atmosphere and absorb sunlight and solar radiation that have bounced off the earth's surface Answer : (d)

Refineries, automobiles and industries release the oxides of carbon, sulphur and nitrogen. The propellants used for jet engine release the halogenated paraffin compounds called fluorocarbons and chlorofluorocarbons. Answer : (d)

Excess of nitrate in drinking water is unsafe for human health and fatal for infants. It reacts with haemoglobin and forms non-functional methaemoglobin that impairs oxygen transport. This is called blue baby syndrome. Answer : (d)

Bronchitis is an inflammation of the lining of your bronchial tubes, which carry air to and from your lungs. Causes for bronchitis are as follows: 1) a virus, for example, a cold or flu virus a bacterial infection 2) exposure to substances that irritate the lungs, such as tobacco smoke, dust, fumes, vapors, and air pollution 3) genetic factors Answer : (c)

Biomagnification, also known as bioamplification or biological magnification, is any concentration of a toxin, such as pesticides, in the tissues of tolerant organisms at successively higher levels in a food chain. Since persistant pesticides magnify in higher level of food chain. It is more hazardous in top carnivores. Answer : (d)

Chlorinated hydrocarbons are not soluble in water. They tend to combine with the adipose or the fatty tissues in the body of animals, including the humans. Answer : (c)

The greenhouse effect is a natural process that warms the Earth's surface. Temperature of earth's surface increases because of green house gases such as carbon dioxide. Answer : (d)

The producer is required initially for the availability of organic food. The consumer will consume the organic food prepared by the producer and will also make an equilibrium in the environment by being a part of the nutrient cycle. A decomposer will breakdown the dead organic from the dead bodies of producer and consumer. So, these are required in a functional ecosystem. The presence of polluter is undesirable as it would distort the environment, making it difficult for the biotic and abiotic components to keep their sustenance. Answer : (b)

Hydroelectric power is the cleanest form of energy. It does not emit any pollutants. Automobiles and industries emit pollutants like oxide of nitrogen, sulphur and carbon. Pollen grain are not pollutant but are known allergens and when inhaled by person can result in difficulty in breathing. Answer : (b)

BOD is a measure of the amount of oxygen required to remove waste organic matter from water in the process of decomposition by aerobic bacteria (those bacteria that live only in an environment containing oxygen). BOD is used, often in wastewater-treatment plants, as an index of the degree of organic pollution in water. Answer : (b)

Green house gasess are CO2,H2O,CH4, O 3. N2O, CFC Answer : (b)

UVB light causes destruction of hydrogen bonds between complementary DNA strands. This results in thymine base pairs next to each other in genetic sequences to bond together into pyrimidine dimers, a disruption in the strand, which reproductive enzymes cannot copy. It causes sunburn and it triggers the production of melanin Answer : (d)

According to Central Pollution Control Board (CPCB), particulate size 2.5 micrometers or less in diameter (PM 2.5) are responsible for causing the greatest harm to human health. These fine particulates can be inhaled deep into the lungs and can cause breathing and respiratory symptoms, irritation, inflammations and damage to the lungs and premature deaths Answer : (c)

Leaves are stomata via which gas exchange as well as transpiration occurs, hence air pollution mostly affects leaves. Answer : (a)

A mere 0.1 per cent impurities make domestic sewage unfit for human use Answer : (d)

Solar radiation do not worm atmosphere directly while reaching earth, radiation makes surface of the earth hot, which radiates long wave The outgoing long wavelength radiation emitted by the Earth is partially to totally absorbed by the greenhouse gases of water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and tropospheric ozone (O3). Answer : (a)