The true statement is:
The human body uses 20 amino acids to form all types of proteins.
The other statements are not accurate:
- Amino acids form a polypeptide chain via peptide bonds, not carbon-carbon bonds.
- Amino acids must be assembled in a specific order to create functional proteins, as the sequence determines the protein's structure and function.
- tRNA (transfer RNA) does not attach to specific proteins; instead, it carries amino acids to the ribosome during protein synthesis, where it matches the amino acid to the corresponding codon on the mRNA.