Environmental Science In Agricultural — Part 2 MCQs with Explanations

Biosphere extends from ocean bottom to mountain tops to a distance of 22.5 km. The biosphere is the global ecological system integrating all living beings including their interaction with the elements of lithosphere, cryosphere, hydrosphere and atmosphere. Life forms live in every part of the Earth's biosphere, including soil, hot springs, inside rocks, deep underground, and high in the atmosphere.

The major pollutants/parts in petrol-based vehicles are Fuel tank, Crankcase and Carburetor. The crankcase is formed by the portion of the cylinder block below the cylinder bores and the stamped or cast metal oil pan that forms the lower enclosure of the engine and also serves as a lubricating oil reservoir or sump. Carburetor, also spelled carburettor, device for supplying a spark-ignition engine with a mixture of fuel and air. Components of carburetors usually include a storage chamber for liquid fuel, a choke, an idling jet, a main jet, a venturi-shaped air-flow restriction, and an accelerator pump.

One hectare of good forest picks up nearly 30,000 kg of CO 2 and releases 10,000 kg of O 2 respectively. With a spacing between lines of 3 meters and a spacing of plants within a line of 3 meters, a planting density of 1,111 trees can be planted in a hectare, which utilizes a huge amount of carbon dioxide from the atmosphere and at the same time release good amount of oxygen.

The important categories of solid waste are Municipal wastes, Industrial wastes and Hazardous wastes. A solid waste is defined as any discarded material that is abandoned by being disposed of, burned or incinerated, recycled or considered "waste-like. It is the unwanted or useless solid materials generated from human activities in residential, industrial or commercial areas. It may be categorized in three ways. According to its origin as domestic, industrial, commercial, construction or institutional.

Natural sink of stratospheric ozone is Freons. Freons is a registered trademark of the Chemours Company and generic descriptor for several halocarbon products. They are stable, nonflammable, low-toxicity gases or liquids which have generally been used as refrigerants and as aerosol propellants. Freons are chlorofluorocarbon compounds that containcontain only carbon, chlorine, and fluorine, produced as a volatile derivative of methane, ethane and propane. These include the chlorofluorocarbons that cause ozone depletion and HCFCs.

Ozone layer of upper atmosphere is being destroyed by Chlorofluorocarbon. In 1976, atmospheric research revealed that the ozone layer was being depleted by chemicals released by industry, mainly chlorofluorocarbons (CFCs). Gaseous CFCs can deplete the ozone layer when they slowly rise into the stratosphere, are broken down by strong ultraviolet radiation, release chlorine atoms, and then react with ozone molecules.

Decreased rainfall in northern areas is due to deforestation in evaporating areas near equator. Deforestation also contributes to decreased evapotranspiration, which lessens atmospheric moisture which in some cases affects precipitation levels downwind from the deforested area, as water is not recycled to downwind forests, but is lost in runoff and returns directly to the oceans. According to one study, in deforested north and northwest China, the average annual precipitation decreased by one third between the 1950s and the 1980s.

The most effective in warming atmosphere is CO 2 . Greenhouse gases like CO 2 absorb some of the heat that the Earth radiates after it warms from sunlight. Larger amounts of these gases trap more heat in Earth's lower atmosphere, causing global warming. Global warming would reach 2.1°C to 3.5°C, and 3.3°C to 5.7°C under the very high GHG emissions scenario.

Among the following Sand particles are chemically inert. Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. The most common constituent of sand, in inland continental settings and non-tropical coastal settings, is silica, usually in the form of quartz, which, because of its chemical inertness and considerable hardness, is the most common mineral resistant to weathering.

Phosphorus cycle is in the form of PO 4 -3 . The phosphorus cycle is the biogeochemical cycle that describes the movement of phosphorus through the lithosphere, hydrosphere and biosphere. Phosphorus occurs most abundantly in nature as part of the orthophosphate ion (PO 4 ) -3 , consisting of a P atom and 4 oxygen atoms. Orthophosphate (PO 4 -3 ), the dominant inorganic P species in nature, is oxidation state (P 5+ ), certain microorganisms can use phosphonate and phosphite (P 3+ oxidation state) as a P source by oxidizing it to orthophosphate.

Temperature is a direct ecological factor. Ecological factors include factors such as light, radiation, temperature, water, chemicals, gases, wind and soil. The direct effect is the effect of exposure on the outcome absent the mediator. Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness.

The most severe pollutant of metals and materials is H 2 SO 4 . Sulfuric acid will exist as particles or droplets in the air if released into the atmosphere. It dissolves when mixed with water. It has moderate acute (short-term) toxicity on aquatic life. Sulfuric acid is very corrosive and would badly burn any plants, birds or land animals exposed to it.

Environmental Science may be defined as the application of all fields of natural science toward solving environmental problems. Also it is the sum of all social, economical, biological and physical or chemical factors which constitute all surroundings of men or living organisms, who is both creator and modular of this environment. Environmental science emerged from the fields of natural history and medicine during the Enlightenment. Today it provides an integrated, quantitative, and interdisciplinary approach to the study of environmental systems.

All the cases of forest land should be approved by State Land Use Board. No State Government can allow use of forest land for non-forestry purposes without the prior approval of the Central Government.

In case of CO 2 in earth's atmosphere disappears, the temperature of earth's surface would Decrease. Carbon dioxide traps heat in the atmosphere, a lessening of atmospheric carbon dioxide concentrations would mean that more heat could escape into space. This would result in a net decrease in the Earth's average temperature, assuming other factors remain the same.

Terrestrial life would become impossible with Change in atmosphere permitting all solar radiations to reach lithosphere. Earth's climate system is a complex system having five interacting components: the atmosphere, the hydrosphere, the cryosphere, the lithosphere and the biosphere. The Earth absorbs most of the energy reaching its surface, a small fraction is reflected. In total approximately 70% of incoming radiation is absorbed by the atmosphere and the Earth's surface while around 30% is reflected back to space and does not heat the surface.

Chlorofuorocarbons release chlorine from the following chemicals which is harmful to ozone layer. Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are fully or partly halogenated hydrocarbons that contain carbon (C), hydrogen (H), chlorine (Cl), and fluorine (F), produced as volatile derivatives of methane, ethane and propane. CFCs contribute to ozone depletion in the upper atmosphere, the manufacture of such compounds has been phased out under the Montreal Protocol, and they are being replaced with other products such as hydrofluorocarbons.

The term biosphere is coined by Eduard Suess. The term "biosphere" was coined by geologist Eduard Suess in 1875, which he defined as the place on Earth's surface where life dwells. The biosphere is virtually a closed system with regard to matter, with minimal inputs and outputs. It can also be termed the zone of life on Earth.

DDT is banned because long persistence in the environment. Dichlorodiphenyltrichloroethane, commonly known as DDT, is a colorless, tasteless, and almost odorless crystalline chemical compound, an organochloride. DDT is similar in structure to the insecticide methoxychlor and the acaricide dicofol. DDT became a prime target of the growing anti-chemical and anti-pesticide movements, and in 1967 a group of scientists and lawyers founded Environmental Defense with the specific goal of enacting a ban on DDT.

Sulphur dioxide affects all membrane systems. Sulphur dioxide is the chemical compound with the formula SO 2 . It is a toxic gas responsible for the odour of burnt matches. Sulphur dioxide irritates the skin and mucous membranes of the eyes, nose, throat, and lungs. High concentrations of SO 2 can cause inflammation and irritation of the respiratory system, especially during heavy physical activity.

Amount of nitrogen fixed by nitrogen fixing organisms per year is about 175 million tonnes. Biological fixation of the atmospheric nitrogen can be estimated at 175 million metric tons per year or about 70% of all nitrogen fixed on the Earth per year, the remaining is by some micro-organisms, autotrophs or heterotrophs 'free' fixers.

Ozone day is celebrated on 16 th September. In 1994, the United Nations General Assembly proclaimed 16 th September the International Day for the Preservation of the Ozone Layer. World Ozone Day is celebrated every year to spread awareness among people about the depletion of Ozone Layer and the measures taken and to be taken to preserve it.

Ecological cycling of Lead is not assisted by microorganisms. The lead cycle is the biogeochemical cycle of lead through the atmosphere, lithosphere, biosphere, and hydrosphere, which has been influenced by anthropogenic activities. Anthropogenic activities have accelerated lead mobilization to the environment. The majority of anthropogenic lead comes from non-ferrous metal manufacturing plants, mining and smelting of ores, stationary and mobile fossil fuel combustion platforms, and lead batteries.

In recent years, there has been an increasing incidence of floods in Northern India because there has been increased deforestation in the catchment areas. Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to non-forest use. Deforestation causes increases in temperatures and changes in the amount and distribution of rainfall generally creating a drier climate. These impacts can affect soil moisture, reducing yields in some areas and increasing flooding in others.

Silent valley (Kerala) is preserved because it contains very rare species of plants and animals. Silent Valley National Park is a beautiful representation of the last remaining rain forest of Kerala. It is located in the Nilgiri hills and has a core area of 89.52 km 2 . It is surrounded by a buffer zone of 148 km 2 . This national park has some rare species of flora and fauna. Silent Valley National Park was explored in 1847 by the botanist Robert Wight.

Hydrological cycle is under the control of Forests and sunlight. Hydrological cycle is a biogeochemical cycle that describes the continuous movement of water on, above and below the surface of the Earth. The level and flow of water depends on the forest cover also the sunlight which evaporates water from the surface.

Cadmium pollution is associated with disease Itai-itai. Itai-itai disease is caused by cadmium (Cd) exposure, produced as a result of human activities related to industrialization, and this condition was first recognized in Japan in the 1960s. Itai-itai disease is characterized by osteomalaecia with severe bone pain and is associated with renal tubular dysfunction.

Plants die in water-logged soils due to Stoppage of root respiration. Waterlogging is excess water in the root zone accompanied by anaerobic conditions. The excess water inhibits gaseous exchange with the atmosphere, and biological activity uses up available oxygen in the soil air and water also called anaerobiosis, anoxia or oxygen deficiency, because of which roots cannot respire causing death of the plant.

Air pollution is maximum in automobile exhausts and chemicals from industries. Air pollution is the contamination of air due to the presence of substances in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or materials. Aerosols are produced by human activities such as the combustion of fossil fuels in automobiles, power plants, and numerous industrial processes. Potential contributors to such an outcome include increased burning activities, traffic, agri-food and chemical industries.

Aitken particles are activated in humid air, cloud's condensed nuclei and Hygroscopic particles. Aitken particles have been defined as those airborne particles having radii less than 0.1 m but larger than those of molecules and small ions. Those with a particle size between 5.0 × 10 -3 and 0.2 μm are called Aitken nuclei, those with a particle size from 0.2 to 1 μm are called large particles, and those with a particle size greater than 1 μm are called giant particles.

The main nitrogen reservoir in the biosphere is Atmosphere. Atmosphere is a layer of gas or layers of gases that envelop a planet and is held in place by the gravity of the planetary body. It is composed of nitrogen (78%), oxygen (21%), argon (0.9%), carbon dioxide (0.04%) and trace gases.

The air pollutants react with lead-based paints, causing decolouration in H 2 S. Lead is added to paint to accelerate drying, increase durability, maintain a fresh appearance, and resist moisture that causes corrosion. It is one of the main health and environmental hazards associated with paint. The paint's lead carbonate reacts with hydrogen sulfide in the air and with acids, which often come from fingerprints.

Every person inhales air daily about 16 kg of. Inhalation of air, as part of the cycle of breathing, is a vital process for all human life. The process is autonomic and does not need conscious control or effort. Inhaled air is by volume 78% nitrogen, 20.95% oxygen and small amounts of other gases including argon, carbon dioxide, neon, helium and hydrogen.

The energy flows in an ecosystem is Multidirectional. An ecosystem consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy and carbon enter ecosystems through photosynthesis, are incorporated into living tissue, transferred to other organisms that feed on the living and dead plant matter, and eventually released through respiration.

Biogeochemical cycle would be affected if decomposers of an ecosystem vanish. A biogeochemical cycle is a pathway by which a chemical substance cycles the biotic and abiotic compartments of Earth. The biotic compartment is the biosphere and the abiotic compartments are the atmosphere, hydrosphere and lithosphere. The fast cycle includes annual cycles involving photosynthesis and decadal cycles involving vegetative growth and decomposition.

Most poisonous pollutant in water is Phosphate. Water pollutants include contamination due to domestic wastes, insecticides and herbicides, food processing waste, pollutants from livestock operations, volatile organic compounds, heavy metals, chemical waste and others. Phosphorus is an essential element for plant life, but when there is too much of it in water, it can speed up eutrophication of rivers and lakes.

Catalytic incinerators are advantageous as they require lower temperatures. In a catalytic incinerator, the gas stream is introduced into a mixing chamber where it is also heated. The waste gas usually passes through a recuperative heat exchanger where it is preheated by post combustion gas. The heated gas then passes through the catalyst bed.

The percentage of energy coming from the sun in re-radiated space is 30%. In total approximately 70% of incoming radiation is absorbed by the atmosphere and the Earth's surface while around 30% is reflected in space and does not heat the surface.

Increased incidences of floods in the plains of North India are due to increased deforestation in catchment areas. Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to a non-forest use. Deforestation causes increases in temperatures and changes in the amount and distribution of rainfall generally creating a drier climate. These impacts can affect soil moisture, reducing yields in some areas and increasing flooding in others.

Acid rain is a rainfall having pH of Less than 5.0. Acid rain is caused by the release of sulfur dioxide and nitrogen oxides into the atmosphere, where they react with water, oxygen, and other chemicals to become sulfuric and nitric acid respectively. The pH of acid-impacted rain is generally below 5.0 on the pH scale.