The Lac Operon is a set of genes that controls the production of lactase the enzyme that digests lactose. In the top picture: The gene is "turned off" resulting in no mRNA being made. In the
bottom picture: The gene is "turned on" allowing the RNA polymerase express the genes,
resulting in production of the lactase enzyme.
which statement is not correct about the lac operon?

The lactose present prevents the production of lactase

Explanation:

This question is describing a set of genes in bacteria called LAC OPERON. Lac operon controls the production of lactase, which is the enzyme that digests lactose. However, this gene can be regulated at the transcription level i.e caused to be transcribed or not depending on certain factors.

According to the question, lac operon, which regulates the production of enzymes will be transcribed and subsequently translated i.e. turned on when there is a substrate (lactose) that the produced enzyme will work on. However, when there is no need of the lactase enzyme or there is absence of lactose (substrate), the lac operon gene is turned off.

Note that, the statement that "The presence of lactose prevents the production of lactase" is not correct.

b. heterotroph

explanation:

the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.