Answer: Mercury has been well known as an environmental pollutant for several decades. As early as the 1950's it was established that emissions of mercury to the environment could have serious effects on human health. These early studies demonstrated that fish and other wildlife from various ecosystems commonly attain mercury levels of toxicological concern when directly affected by mercury-containing emissions from human-related activities. Human health concerns arise when fish and wildlife from these ecosystems are consumed by humans.
During the past decade, a new trend has emerged with regard to mercury pollution. Investigations initiated in the late 1980's in the northern-tier states of the U.S., Canada, and Nordic countries found that fish, mainly from nutrient-poor lakes and often in very remote areas, commonly have high levels of mercury. More recent fish sampling surveys in other regions of the U.S. have shown widespread mercury contamination in streams, wet-lands, reservoirs, and lakes. To date, 33 states have issued fish consumption advisories because of mercury contamination.
These continental to global scale occurrences of mercury contamination cannot be linked to individual emissions of mercury, but instead are due to widespread air pollution. When scientists measure mercury levels in air and surface water, however, the observed levels are extraordinarily low.
Explanation:
Answer:
Horns and columns.
Explanation:
The spinal cord is the important component of the central nervous system. The spinal cord consists of the nerves of the body and control the reflex actions of the body.
Spinal cord consist of white matter and grey matter. The motor and sensory axons are present on white matter. The white matter covers the grey matter and arranged into the different columns. The grey lies inside the white matter and consists of neuronal cell bodies. The grey matter is completely organised in the horns.
Thus, the answer is horns and columns.
The correct answer is: Heartburn often results when the gastroesophageal sphincter fails to close properly.
The gastroesophageal sphincter is a muscle located at the bottom of the esophagus that has to be relaxed in order to allow food to flow down into the stomach. After it contracts (tightens), the food and the stomach acid can’t flow back up into the esophagus.
When the gastroesophageal sphincter fails to close properly acid reflux occurs and causes the heartburn.
Answer:
expand the scope of the experiment
Explanation:
