Answer:
Nonpoint-source pollution is the opposite of point-source pollution, with pollutants released in a wide area. As an example, picture a city street during a thunderstorm. As rainwater flows over asphalt, it washes away drops of oil that leaked from car engines, particles of tire rubber, dog waste, and trash. The runoff goes into a storm sewer and ends up in a nearby river. Runoff is a major cause of nonpoint-source pollution. It is a big problem in cities because of all the hard surfaces, including streets and roofs. The amount of pollutants washed from a single city block might be small, but when you add up the miles and miles of pavement in a big city you get a big problem.
In rural areas, runoff can wash sediment from the roads in a logged-over forest tract. It can also carry acid from abandoned mines and flush pesticides and fertilizer from farm fields. All of this pollution is likely to wind up in streams, rivers, and lakes.
Airborne pollutants are major contributors to acid rain. It forms in the atmosphere when sulfur dioxide and nitrogen oxides combine with water. Because acid rain results from the long-range movement of those pollutants from many factories and power plants, it is considered nonpoint-source pollution.
Explanation:
The aurora borealis is caused by the collisions between gaseous particles in the Earth's atmosphere.
Answer:
DNA contains four types of nucleotide. These are adenine, thymine, guanine, and cytosine. Uracil is the fifth and final nucleotide but it is only present in certain forms of RNA. So back to the question nucleotides are the basic structural unit of nucleic acids.
Answer:
Option D, appear in the urine
Explanation:
It is mentioned in the question that Tm for a particular amino acid is 120 mg/100 ml , but the concentration of amino acid in blood is 230 mg/100 ml. Thus, there is an excess of amino acid in blood. The excess amino acid is drained into kidney during blood purification which ultimately appear in the urine.
Thus, option D is correct
