$RNA$ shows the following characters $EXCEPT$ . . . . . . .

Given below are two statements:
Statement $I$: Catalytic RNAs are called ribozymes.
Statement $II$: $RNA$ can undergo mutations,replicate,and catalyse reactions.
In the light of the above statements,select the correct option given below:

Which of the following discoveries led to the term '$RNA$ world' being coined in $1980$?

Which of the following bases is present only in $R.N.A$?

Which of the following biological molecules acts as a messenger?

$RNA$ contains: