Which of the following codons acts as a stop signal?

What is not true for genetic code?

Out of $64$ codons,$61$ codons code for $20$ different amino acids. What is this property of the genetic code called?

Give differences: Codons and Anticodons.

If in a test tube,$mRNA$ of $E. coli$ cells and $tRNAs$ from the body of rats are taken and a sufficient number of amino acids are added,then the polypeptide synthesized will be of the nature of

The number of codons effective in coding twenty amino acids is: