Answer: The greenhouse gas emissions from the extraction of bitumen and the use of large quantities of water.
Explanation:
Bitumen is a natural flammable organic matter formed from kerogen in the process of petroleum generation, which is soluble in carbon disulfide. Asphalt and mineral wax are examples of hydrocarbons which are part of bitumen. Conventional oil is extracted by wells while <u>oil sands deposits are extracted using surface mining sectioning techniques, or are flowed to wells by in situ techniques that reduce bitumen viscosity by steam and/or solvents.</u> So, unlike crude oil extracted in oil wells, bitumen requires an open-pit mining operation, in which large tracts are washed with a mixture of water and chemicals to separate the bitumen from a mixture of sand and clay.
Two consequences of this practice are:
- The greenhouse gas emissions from the extraction of bitumen are larger than the extraction of conventional oil. The emissions produced contribute to enhance the greenhouse effect and cause global warming. The greenhouse effect occurs when certain gases retain part of the energy emitted by the earth's soil when heated by the sun's radiation. This phenomenon occurs naturally, and thanks to it, the average temperature of the Earth is about 14º C (57.2 °F). The problem occurs when these greenhouse gases increase in the atmosphere and the amount of energy that is not released into space also increases and, with it, the Earth's temperature.
- The extraction of bitumen from oil sands requires the use of large quantities of water, and even though water used here can be recycled, only a small amounts is returned to the natural cycle. Also, spills from the transportation of the oil could damage soils and waterways, increasing water pollution. This toxic water could get into surface.
All protozoans are unicellular (are a single cell). Similar to the plant-like protists, protozoa are found in nearly all aquatic habitats. Protozoa play a key role in maintaining the balance of ecosystems. They are an important food source for organisms higher up in food chains.
Answer:
Binomial system of nomenclature
<h2><u>
Answer:</u></h2>
<em>Wildebeests live in great numbers on East Africa's vast plains, where dramatic wet and dry seasons cause a bounty of grass at sometimes, and a dearth of good grazing at others. To survive, the wildebeest must migrate to find food.</em>
<h2><u>
Explanation:</u></h2>
<em>The wildebeest migrate around the Serengeti, and into the Masai Mara for the sole purpose of following the rainfall. For their calving from December - March they always begin their cycle in the Southern Serengeti area of Ndutu and follow wherever the grass is green. Wildebeest migrate on a loop path through Tanzania and Kenya following the seasonal rains even when that involves passing through dangerous territory. This is a modal window. Wildebeest, also called gnus, are members of the antelope family.</em>
