Which of the following triplet codons correctly represents a start or stop signal for protein synthesis?

For the genetic code,choose the correct option for the given statements. Where $T$ stands for True and $F$ stands for False.
$(1)$ Phenylalanine $(Phe)$ amino acid is coded by more than three codons.
$(2)$ The codon is read in $t-RNA$ in a contiguous fashion.
$(3)$ $UUC$ would code for phenylalanine.
$(4)$ $AUG$ codes for Methionine.

Dr. Khorana prepared an artificial mRNA containing $CUCUCUCUCU$ nucleotides; its translation resulted in the formation of a polypeptide chain bearing alternately arranged . . . . . . and . . . . . . amino acids,respectively.

$A$ single base mutation in a gene may not 'always' result in loss or gain of function. Do you think the statement is correct? Defend your answer.

The 'one gene-one enzyme' hypothesis was proposed by . . . . . . .

Explain the contributions of the following scientists:
$1.$ George Gamow
$2.$ Marshall Nirenberg