Clean Air Act (CAA), US Federal law, passed in 1970 and later amended, to prevent air pollution and thereby protect the ozone layer and and promote public health. The clean air act gave the federal environmental protection agency the power it needed to take effective action to fight environmental pollution. Hope this helps シ
Initiator proteins break hydrogen bonds separating short length of DNA, AT base pairs are held together by fewer hydrogen bonds than GC pair. Thus AT pairs are easier to pull apart, At rich regions are typically found in the replication origins. Replication origins are site at which DNA is first opened.