Enzymes are mainly globular proteins containing 100-1000 different amino acids. They act as biocatalysts in a living organism and highly specific. They catalyse various chemical reactions in our body. For example, enzyme Trypsin breaks proteins into amino acids. So (i) and (iv) are correct.

Nucleic acids are long-chain polymers of nucleotides. Nucleotides consist of the sugar ring, base and phosphodiester linkage. So their structures are not similar to proteins.

Therefore, options (ii) and (iii) are wrong.