Ans.
Lac (lactose) operon in a type of bacterial operon, which shows a cluster of genes that are regulated by a single promoter. It is composed of an operator, promoter, a terminator, and three structural genes (lacA, lacY, and lacZ), which are responsible for the transport and breakdown of lactose.
The lac operon is an inducible operon as it gets activated in the presence of lactose and expressed its functional genes in the form of proteins (or enzymes) for lactose metabolism.
Thus, the correct answer to be fill in first blank is 'inducible' and in second blank is 'lactose.'
(see attached picture)
Answer - D. (The genetic code)
The genetic code is the nucleotide base sequence on DNA (with which information is encoded within genetic material). The nucleotide base sequence<span> codes for a sequence of amino acids, which are in turn used by living cells as the basic building blocks of proteins.</span>