Unusual nucleosides that are found in mature trna molecules are added during:
a. transcription initiation
b. transcription elongation
c. transcription termination
d. post transcriptional modification
e. it is not currently known when the unusual nucleosides are added

The correct answer will be option-D.

Explanation:

tRNA or transfer RNA is an adaptor molecule used during the translation process to add specific amino acids to the polypeptide.

The tRNA structure contains modified bases like inosine which is the first nucleotide of the anticodon loop and has the ability to form a hydrogen bond with more than one base of the codon.  Inosine is derived from the adenine base during post-transcriptional modification of mRNA by methylation.

Thus, option-D is the correct answer.

carbohydrates: (starches and sugars) composed of carbon, hydrogen, and oxygen.

lipids: (fats, oils, and waxes) are made of carbon and hydrogen atoms.

nucleic acids: contain hydrogen, oxygen, nitrogen, carbon, and phosphorus. they are polymers of nucleotides. a nucleotide has three parts, a 5-carbon sugar, a phosphate     (-po⬇️4) group, and a nitrogenous base.

proteins: made up of nitrogen, carbon, hydrogen, and oxygen. they are polymers of amino acids.

b because they naturally adapt to their environment plz mark brainliest

explanation: