Answer:
At almost the opposite point on the Earth's surface, the "P" waves reappear. The shadow zone exists because the waves are refracted as they pass through the boundary between the mantle and the core and are diverted from their original paths.
Light reaction occurs in presence of light while in dark reaction light is not needed
Answer:
If the water is initially hot, cooled water at the bottom is denser than the hot water at the top, so no convection will occur and the bottom part will start freezing while the top is still warm. This effect, combined with the evaporation effect, may make hot water freeze faster than cold water in some cases.
Explanation:
Answer:
The correct answers are A, B and D. The Clean Air Act was important because it emphasized cost-effective methods to protect the air; encouraged people to study the effects of dirty air on human health; and created a regulation that makes any activities that pollute the air illegal.
Explanation:
The Clean Air Act is a federal federal law designed to control air pollution nationwide. The Environmental Protection Agency (EPA) is required to develop and enforce the regulations to protect the general public from exposure to air pollutants that are known to be dangerous to human health. The 1963 law established a basic research program, which was expanded in 1967. The main changes to the law, which require regulatory controls of air pollution, were promulgated in 1970, 1977 and 1990.
The 1970 amendments significantly expanded the federal mandate by demanding broad federal and state regulations, both for fixed sources of pollution (industrial) and mobile sources.
In 1990 provisions were added to deal with acid rain, depletion of the ozone layer and toxic air pollution, and a program of national permits of fixed sources was established. Also new requirements were established for the reformulation of gasoline, the adjustment of Reid vapor pressure (RVP), which measures the volatility of gasoline; and the norms to control the evaporation emissions of the gasoline.
The Clean Air Act is important because it was the first important environmental law in the United States to include a disposition regarding citizen demands. Numerous local and state governments have promulgated similar laws, either the execution of federal programs or to fill important loopholes at the local level in federal programs.
I believe that it is D. All of the above.
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