Answer:
The correct answer to the question: What did the Clean Air Act allow citizens to do that no previous U.S. environmental law had allowed, would be: it was the first law that considered citizen lawsuits against the correct enforcement of the statutes stated in the Act.
Explanation:
The Clean Air Act, which was passed originally in 1963, and which has been amended since, with its last update being in the 1990´s, became the first time that the U.S government not only established federal funding for environmental issues, but also regulated environmental topics through EPA (Environmental Protection Agency, 1970) and considered the power that citizens could have to ensure the enforcement of the statutes and provisions considered in the Act. This consideration of citizen suits, is the most important  and relevant difference with earlier environmental laws.
 
        
             
        
        
        
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Answer:
Red-capped Robin is the group of Robins that share a more recent common ancestor with the Norfolk Island robins.
Explanation:
Red-capped Robin is the group of Robins that share a more recent common ancestor with the Norfolk Island robins, this can be seen by the degree of genetic similarity between these two species, since the Red-capped Robin has 98.2% of genetic similarity .
When two species have the same common ancestor, these species have great genetic similarity and the more recent this ancestry is, the greater the genetic similarity between the species.
 
        
             
        
        
        
Answer:
read below ! 
Explanation:
it's basically the layers from the earth's crust, all the way out to space. there are 5 layers in all, and they all protect earth from the things in space, and the suns rays. it keep gravity in, and things like that !!
i hope this is what you meant, and that it helped!! :)