Methane is produced when bacteria break down the organic matter in moist places that lack oxygen, such as swamps, natural wetlands, paddy fields, landfills and digestive tracts of cattle, sheep and termites.

Banaras Hindu University (BHU); Murugappa Chettiar Research Centre (MCRC), Chennai and IIT Kharagpur are among the leading research groups working on biological, biomass and other renewable energy routes to produce hydrogen. The BHU, IIT Chennai and the National Physical Laboratory are working on the hydrogen storage methods. The BHU has modified a commercially available motorcycle (100 cc, four strokes) and a three-wheeler (175 cc, four strokes) to operate on hydrogen as a fuel.

Pyrolysis is a process of chemical decomposition of organic matter brought about by heat. In this process, the organic material is heated in the absence of air until the molecules thermally break down to become a gas comprising smaller molecules (known collectively as syngas). Gasification can also take place as a result of partial combustion of organic matter in the presence of a restricted quantity of oxygen or air. These methods are suitable for obtaining energy from wastes rich in organic content and low in moisture.

Only 1 is true.

Van Mahotsav is a week-long festival of tree planting that is organised every year in the month of July all across India and lakhs of trees are planted. It is one of the best ways of preventing Earth from global warming. 

Most of the terrestrial hotspots are found at the Tropics. A variety of approaches has been utilised to identify areas of high species richness and endemism. The term 'hotspots' was coined by Norman Myers (1988) to indicate areas of high conservation value that are facing significant threats to conservation. In general, species diversity per unit area tends to increase with decreasing latitude, with highest diversity found in the Tropics. 

The gas which leaked from the Union Carbide Plant in Bhopal in 1984 was methyl isocyanate. 

The amount of carbon dioxide in the atmosphere has increased in recent years. Environmentalists suggest this change is a direct result of the overcutting of forests and the increased use of fossil fuels. Deforestation and the use of fossil fuels are both suspected of increasing the amount of carbon dioxide in the atmosphere. This is of worldwide concern because of its potential effects on the environment, such as global warming due to the weakening of the ozone layer which protects the earth from harmful solar radiation. 

The neritic zone, also called coastal waters, the coastal ocean or the sublittoral zone, is the part of the ocean extending from the low tide mark to the edge of the continental shelf, with a relatively shallow depth extending to about 200 metres (110 fathoms or 667 feet). The neritic zone has generally well-oxygenated water, low water pressure, and relatively stable temperature and salinity levels. The benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers. Organisms living in this zone are called benthos. For example, the benthic invertebrate community, including crustaceans and polychaetes.

The Western Ghats are home to four tropical and subtropical moist broadleaf forest ecoregions, i.e. the North-Western Ghats moist deciduous forests, North-Western Ghats montane rain forests, South-Western Ghats moist deciduous forests, and South-Western Ghats montane rain forests. The evergreen Wayanad forests of Kerala mark the transition zone between the northern and southern ecologic regions of the Western Ghats. The southern ecologic regions are generally wetter and more species-rich.

A nutrient cycle (or ecological recycling) is the movement and exchange of organic and inorganic matter back into the production of living matter. The process is regulated by food web pathways that decompose matter into mineral nutrients. In biology, detritus is non-living particulate organic material (as opposed to dissolved organic material). It typically includes the bodies or fragments of dead organisms, as well as faecal material.

A temperate grassland or shrubland biome is known commonly as steppe in central Asia, prairie in North America, and pampas in South America.

The Dobson unit (DU) is a unit of measurement of the columnar density of a trace gas in the Earth's atmosphere. It originated and continues to be widely used as a measure of total-column ozone, which is dominated by ozone in the stratospheric ozone layer.

The river Kosi is known as the 'Sorrow of Bihar' as it flows from Nepal to India and has caused widespread human suffering in the past through flooding and very frequent changes in course. It is river Damodar which is often labelled as the ‘Sorrow of Bengal’. Over the last 250 years, the river Kosi has shifted its course over 120 km (75 miles) from East to West. Its unstable nature has been attributed to the heavy silt it carries during the monsoon season which causes flooding in India that has extreme effects. 

Nitrogen fixation is a process by which nitrogen (N₂) in the atmosphere is converted into ammonia (NH₃). Nitrogen fixation also refers to other biological conversions of nitrogen. Biological nitrogen fixation (BNF) occurs when atmospheric nitrogen is converted to ammonia by an enzyme called nitrogenase. All the given microorganisms can fix atmospheric nitrogen.

Coral reefs in India cover an area of 2375 square kilometres, with 4 major coral reef areas identified for intensive conservation and management. These are Gulf of Mannar, Gulf of Kutchh, Lakshwadeep Islands and Andaman and Nicobar Islands. Together, they contain 80% of global coral diversity.

Some species of birds have gone extinct in recent times, including the Pink-headed Duck (Rhodonessa Caryophyllacea) and the Himalayan Quail (Ophrysia Superciliosa).

Lonesome George was a male Pinta Island tortoise (Chelonoidis nigra abingdonii) and the last known individual of the subspecies, also known as the Galápagos' tortoise. In his last years, he was known as the rarest creature in the world. George served as a potent symbol for conservation efforts in the Galápagos and internationally.

The Red Data Book is the state document established for documenting rare and endangered species of animals, plants and fungi, as well as some local sub-species that exist within the territory of the state or country. This book provides central information for studies and monitoring programmes on rare and endangered species and their habits.

Biosphere reserves are another category of protected areas. Under this, a large area is declared as a biosphere reserve where wildlife is protected, but local communities are allowed to continue to live and pursue traditional activities within the reserve. The Indian government has established 18 biosphere reserves of India, (categories roughly corresponding to IUCN category V protected areas), which protect larger areas of natural habitat (than a National Park or Animal Sanctuary), and often include one or more National Parks and preserves, along buffer zones that are open to some economic uses.

The Indian Vulture and the Indian White-rumped Vulture, G. bengalensis species have suffered a 99%-97% population decrease in Pakistan and India, and between 2000-2007, annual decline rates of this species and the Slender-billed Vulture averaged over 16%. The cause of this has been identified as poisoning caused by the veterinary drug diclofenac. The drug is believed to be swallowed by vultures with the flesh of dead cattle which were given diclofenac in the last days of life. Diclofenac causes kidney failure in several species of vultures. As of August 2011, the ban for veterinary use has been in place for approximately a year, but diclofenac was still being used for animals throughout India.

The ozone hole is visible during the Antarctic spring, from September to early December, as strong westerly winds start to circulate around the continent and create an atmospheric container.

Troposphere: The layer of the atmosphere closest to the earth is the troposphere. It begins at the surface of the earth and extends to about 4-12 miles. The temperature of the troposphere decreases with height. This layer is known as the lower atmosphere. Stratosphere: Above the troposphere is the stratosphere, which extends to about 30-35 miles above the earth's surface. Temperature rises within the stratosphere, but still remains well below freezing. Mesosphere: From about 35 to 50 miles above the surface of the earth, lies the mesosphere, where the air is especially thin and molecules are great distances apart. Temperatures in the mesosphere reach a low of -184°F (-120°C). The stratosphere and the mesosphere are the middle atmosphere. Thermosphere: The thermosphere rises several hundred miles above the earth's surface, from 50 miles up to about 400 miles. Temperature increases with height and can rise to as high as 3,600°F (2000°C). Nonetheless, the air would be cold because the hot molecules are so far apart. This layer is known as the upper atmosphere. Exosphere: Extending from the top of the thermosphere to 6200 miles (10,000 km) above the earth is the exosphere. This layer has very few atmospheric molecules, which can escape into space.

1. As carbon dioxide is absorbed, it reacts with ocean water to form carbonic acid. This process is called ocean acidification. Over time, this acid causes the pH of the oceans to decrease, making ocean water more acidic. This can have drastic consequences on corals and other marine life.
   1. Some areas show increase in agricultural growth due to global warming as increased carbon dioxide levels may accelerate the growth of some crops. Arctic, Antarctic, Siberia and other frozen regions of earth may experience more plant growth due to milder climates.

All types of asbestos fibres are known to cause serious health hazards in humans. While it is agreed that amosite and crocidolite are the most hazardous asbestos fibre types, chrysotile asbestos has produced tumors in animals and is a recognised cause of asbestosis and malignant mesothelioma in humans.