How many genetic codons are considered stop codons (nonsense codons)?

Which of the following is not an anticodon?

In $mRNA$,$AUG$ is the initiation codon and $UAA$,$UAG$,and $UGA$ are termination codons; therefore,a polypeptide cannot be synthesized beyond any of these triplets to the end of the $mRNA$. Which one of the following $mRNA$ sequences can be translated completely?

In sickle cell anaemia,glutamic acid is replaced by valine. Which of the following codes for glutamic acid?

Select the correct option for George Gamow.

In the genetic code, a sequence of three consecutive bases specifies a/an..........