Generally nonsense is much much worse. It creates a premature stop code which can throw off the entire chain of codons and makes things much much worse. A good way to remember this is that the nonsense mutations make the codons not make sense.
The respiratory systems function is to breathe.
Bonds issued by the U.S. treasury are back by the federal reserve and claim to have no credit risk. Agency bonds also usually have low credit risk. otherwise you just have to look at the bond before you invest and find out what dink of credit risks are involved.
