Some regions of a polypeptide may coil or fold back on themselves. this is called and the coils or folds are held in place by see concept.

The options are

A. secondary structure ... hydrogen bonds

B. secondary structure ... peptide bonds

C. tertiary structure ... hydrogen bonds

D. primary structure ... covalent bonds

E. tertiary structure ... covalent bonds

THE CORRECT ANSWER IS A.

A. secondary structure ... hydrogen bonds

Explanation:

The secondary structure of a polypeptide shows the localized regions of its organised structure being upheld by hydrogen bonds among the major groups

-NH and C = O

At the same time, it inhibits the hydrogen bonds of the side chains from influencing the reaction process.

The polypeptide secondary structure shows the dexterity to curl or fold as sustained by the polypeptide chains.

answer: the correct option is d. enzyme

lactase and carbonic anhydrase are the examples of enzymes.

lactase is an enzyme, which is present in the small intestine of mammals. it in the digestion of the disaccharide, lactose ( milk sugar) by converting it into two monosachharide, which are glucose and galactose.

carbonic anhydrase is present in the red blood cells. this enzyme plays significant role in the transport of co₂. it in the conversion of co₂ and h₂o into carbonic acid, which is then dissociated into bicarbonate ions and hydrogen ions.