Directions for the following 2 (two) items:
Read the following passage and answer the two items that follow. Your answers to these items should be based on the passage only.
Passage
Crude mineral oil comes out of the earth as a thick brown or black liquid with a strong smell. It is a complex mixture of many different substances, each with its own individual qualities. Most of them are combinations of hydrogen and carbon in varying proportions. Such hydrocarbons are also found in other forms such as bitumen, asphalt and natural gas. Mineral oil originates from plants that live in the sea. Over millions of years, these dead creatures form large deposited under the sea-bed; and ocean currents cover them with a blanket of sand and silt. As this mineral hardens, it becomes sedimentary rock and effectively shuts out the oxygen, so preventing the complete decomposition of the marine deposits underneath. The layers of sedimentary rock become thicker and heavier. Their pressure produces heat, which transforms the tiny carcasses into crude oil in a process that is still going on today.
Mineral oil deposits under the sea do not get completely decomposed because they
are constantly washed by the ocean currents.
become rock and prevent oxygen from entering them.
contain a mixture of hydrogen and carbon.
are carcasses of organisms lying in saline conditions.
Passage - 1
The law in many parts of the world increasingly restricts the discharge of agricultural slurry into watercourses. The simplest and often the most economically sound practice returns the material to the land as semisolid manure or as sprayed slurry. This dilutes its concentration in the environment to what might have occurred in a more primitive and sustainable type of agriculture and converts pollutant into fertilizer. Soil microorganisms decompose the organic components of sewage and slurry and most of the mineral nutrients become available to be absorbed again by the vegetation.
The excess input of nutrients, both nitrogen and phosphorus-based, from agricultural runoff (and human sewage) has caused many 'healthy' oligotrophic lakes (low nutrient concentrations, low plant productivity with abundant water weeds, and clear water) to change to eutrophic condition where high nutrient inputs lead to high phytoplankton productivity (sometimes dominated by bloom-forming toxic species). This makes the water turbid, eliminates large plants and, in the worst situations, leads to anoxia and fish kills; so called cultural eutrophication. Thus, important ecosystem services are lost, including the provisioning service of wild-caught fish and the cultural services associated with recreation.
The process of cultural eutrophication of lakes has been understood for some time. But only recently did scientists notice huge ' dead zones' in the oceans near river outlets, particularly those draining large catchment areas such as the Mississippi in North America and the Yangtze in China. The nutrient-enriched water flows through streams, rivers and lakes, and eventually to the estuary and ocean where the ecological impact may be huge, killing virtually all invertebrates and fish in areas up to 70,000 km2 in extent. More than 150 sea areas worldwide are now regularly starved of oxygen as a result of decomposition of algal blooms, fuelled particularly by nitrogen from agricultural runoff of fertilizers and sewage from large cities. Oceanic deal zones are typically associated with industrialized notions and usually lie off countries that subsidize their agriculture, encouraging farmers to increase productivity and use more fertilizer.
According to the passage, why should the discharge of agricultural slurry into watercourses be restricted?
1. Losing nutrients in this way is not a good practice economically.
2. Watercourses do not contain the microorganisms that can decompose organic components of agricultural slurry.
3. The discharge may lead to the eutrophication of water bodies.
Select the correct answer using the codes given below:
According to the passage, what are the effects of indiscriminate use of fertilizers?
1. Addition of pollutants to the soil and water.
2. Destruction of decomposer microorganisms in soil.
3. Nutrient enrichment of water bodies.
4. Creation of algal blooms.
Select the correct answer from the codes given below:
What is/are the characteristics of a water body with cultural eutrophication?
1. Loss of ecosystem services
2. Loss of flora and fauna
3. Loss of mineral nutrients
Select the correct answer using the code given below:
