In which of the following places is the Vulture Conservation and Breeding Centre located?

The correct answer is C, methane and carbon dioxide. Biogas is produced when cattle dung, crop waste and sewage are broken down by bacteria in a closed tank without air, a process called anaerobic digestion. The gas that collects is about 55 to 70 per cent methane and most of the rest is carbon dioxide, with small traces of hydrogen sulphide and water vapour. Methane is the part that burns, which is why biogas gives a clean blue flame and is used for cooking and lighting in villages; the slurry left behind is a good manure. A gobar gas plant thus turns waste into fuel and fertiliser at the same time. A is wrong because hydrogen is not a major part of biogas. B is wrong because helium is an inert gas that no bacteria produce. D is wrong because nitrogen is present only in traces and does not burn. Exam tip: biogas is mainly methane with carbon dioxide, made by anaerobic digestion, and its slurry is used as manure.

The correct answer is A, Tsunami. A tsunami is caused by an undersea earthquake, a volcanic eruption or a landslide on the ocean floor, and has nothing to do with the ozone layer.

The ozone layer lies in the stratosphere, roughly 15 to 35 km above the ground, and absorbs most of the harmful ultraviolet radiation of the Sun. Chlorofluorocarbons used in refrigerators, air conditioners and aerosol sprays release chlorine that destroys ozone, which is why the Montreal Protocol of 1987 phased them out. World Ozone Day is observed on 16 September.

Option B is a real result, because extra ultraviolet radiation damages skin cells and raises the risk of skin cancer. Option C is a real result, since a thinner layer lets more ultraviolet rays reach the Earth. Option D is a real result, as ultraviolet exposure weakens the immune system, and it also causes cataract and harms crops and plankton.

Exam tip: ozone holes bring skin cancer, cataract and weak immunity; tsunamis come from the sea floor, not the sky.

The correct answer is A, Schedule I. This schedule carries the species given the highest degree of protection, for which hunting is barred throughout India and the penalties are the severest the Act provides, with the offence being cognizable and non bailable. Both the tiger and the Asian elephant are in it, and both are also in Appendix I of CITES, so that international commercial trade in them is prohibited.

Option B, option C and option D name schedules that carry species with lesser degrees of protection and lighter penalties. A candidate should link the schedule to the animal: the tiger, the elephant, the one horned rhinoceros, the snow leopard, the great Indian bustard and the lion tailed macaque all belong to the first schedule, which is the list examiners draw upon most often.

The correct answer is A, New Delhi. The Global Tiger Forum was formed in the nineteen nineties as an international body of tiger range countries and others working for the conservation of the species, and its secretariat is in New Delhi, which reflects the share of the world's wild tigers that India holds.

Option B, Kathmandu, is the headquarters of the South Asian Association for Regional Cooperation and of the International Centre for Integrated Mountain Development, not of the Forum. Option C, Geneva, houses the secretariat of the Convention on International Trade in Endangered Species, among many other international bodies. Option D, Gland in Switzerland, is the headquarters of the International Union for Conservation of Nature, which publishes the Red List, and of the World Wide Fund for Nature.

The correct answer is A, 29 July. The day was agreed upon at the tiger summit held at St Petersburg in 2010, where the thirteen tiger range countries adopted the goal of doubling the number of wild tigers, and it is marked every year to draw attention to the conservation of the species.

Option B, 12 August, is World Elephant Day, the pairing that this topic always tests. Option C, 5 June, is World Environment Day, marked since the Stockholm Conference of 1972. Option D, 3 March, is World Wildlife Day, chosen because the Convention on International Trade in Endangered Species was signed on that date in 1973. All four are days worth remembering together, since a single question often mixes them, and the safest way is to tie each date to the event behind it rather than to learn the list by rote.