Answer:
Option A
Explanation:
Thyroid is primarily caused by lack of iodine but there are other reasons as well that lead to increased size of the thyroid gland. Some of these reason is
a) over- or underproduction of thyroid hormones
b) Nodules in the glans
Some times, due to overstimulation immune system itself attack the thyroid gland thereby producing excess thyroxine and hence causing the thyroid to swell
Thus, Option A is correct
c. cell wall, vacuole
Among the choices above, the two features that indicate that a cell is a plant cell is the cell wall and vacuole. The cell wall can only be found in plant cells. It is the rigid cell that surrounds the cell membrane. The vacuole of a plant cell and animal cell are way too different. The vacuole of an animal cell is usually more than one and small, even smaller that that of the plant cell. On the other hand, the vacuole of the plant cell is only one in fact a large one that takes up almost 90 percent of the volume of the cell
In the given case, no antibiotic is needed for dental procedures.
Based on the updated recommendations from the American Heart Association, there is no need to take a precautionary antibiotic prior to dental proceedings for the majority of people.
It has been suggested by AHA that only those who are at greatest threat of bad consequences from infective endocarditis needs to get the short-term preventive antibiotics prior to routine dental approaches.
It has been recommended by the AHA guidelines that various of the people who have taken preventive antibiotics in the past no longer need them, these include the individuals with the conditions, like mitral valve prolapse, ventricular septal defect, bicuspid valve disease, rheumatic heart disease, and others.
In the United States, flu season occurs in the fall and winter. While influenza viruses circulate year-round, most of the time flu activity peaks between December and February, but activity can last as late as May.
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.
