Which of the following peptide chain is removed during the maturation of proinsulin into insulin?

Consider the following statements about insulin

$I$. Human insulin is made-up of $51$ amino acids arranged in two polypeptide chains

$II$. The two polypeptide chains are interconnected by two disulphide bridges

$III$. In mammals including humans, insulin is synthesized as a pro-hormone, which contains an extra stretch called the Cpeptide

$IV$. $C-$peptide is not present in the mature insulin

Which of the statements given above are correct?

Golden rice is a transgenic crop of the future with the following improved trait

A distinct mechanism that usually involves a short segment of $DNA$ with remarkable capacity to move from one location in a chromosome to another, this is called