Answer: Option C) "excludes agricultural runoff"
Explanation:
The Clean Water Act (CWA) established in 1972 is a federal law made in United States to address the adverse effect of water pollution. The act was aimed to maintain the physical, chemical, and biological integrity of the nation's waters.
A major shortcoming of the Clean Water Act (CWA) is agricultural runoff which is a nonpoint source (NPS) pollution. Large scale agriculture activities have an adverse impact on groundwater and surfacewater as they carry heavy fertilizer, pesticide and water inputs.
The federal CWA establish water quality standards and total maximum daily loads (TMDLs) to asses the pollution caused by agricultural water with the help of regulatory mechanisms.
Hence, the correct option C.
The meteorite was probably 1<span>0 to 15 km (6.2 to 9.3 mi) wide</span> and affected the entire planet through a proces called "impact winter". As the name suggests, an impact winter is a period of low temperature produced by a huge cloud of ash and dust that blocks sunlight. Since sunlight is essential for plants to survive, if the sun rays are blocked by this cloud, all animals that depend on those plants (including dinosaurs) will die. The meteorite could have created such a cloud upon hitting the earth.
Gas chromatography (GC) is a method of separating mixed compounds.
The separation will depend on each compound's retention time. Compounds with
higher molecular weights will elute out slower than those with lower molecular
weight. This is due to their difference in boiling points. The larger the
structure, the higher the boiling point.
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