Natural levels of nitrate in Minnesota groundwater are usually quite low (less than 1 milligram per liter [mg/L] of nitrate-nitrogen). However, where sources of nitrate such as fertilizers, animal wastes, or human sewage are concentrated near the ground surface, nitrate may seep down and contaminate the groundwater. Elevated nitrate levels in groundwater are often caused by run-off from barnyards or feedlots, excessive use of fertilizers, or septic systems.
Wells most vulnerable to nitrate contamination include shallow wells, dug wells with casing which is not watertight, and wells with damaged, leaking casing or fittings.
Nitrate contamination of a well is often regarded as a first sign of deteriorating groundwater quality.
It would be the closest as the massive glaciers in that area melted and retreated. Freed from the enormous weight of ice, the land level gradually rose over several thousand years and the waters simply drained off into the ocean, leaving what is now Lake Champlain and a few river valleys.
Answer:
Its Genetic drift
Explanation:
Genetic Drift is a random decrease in genetic variation
Our ears use vibrations to detect sound.
Inside our ears we have an eardrum, this eardrum is connected to three small bones known as Ossicles. When something makes a sound is creates a vibration that makes the eardrum vibrate and pass this vibration through the Ossicles to the Co<span>chlea which allows us the comprehend the sound something is making.
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