The nucleotide sequence of a dna codon is gta. in an mrna molecule transcribed from this dna, the codon has the sequence in the process of protein synthesis, a transfer rna pairs with the mrna codon. the nucleotide sequence of the trna anticodon is the amino acid attached to the trna is

Remember for DNA, G complements C and A complements T (and vice versa). 
Remember for RNA, G also complements C, but A complements U because there is no thymine in RNA. If RNA is being transcribed from DNA, a T (in DNA) transcribes into an A.

You're told that the nucleotide sequence of the DNA codon is GTA. That means the mRNA transcribed is CAU. 

The tRNA sequence pairs with the CAU mRNA sequence. That means the tRNA transcribed is GUA.

Using the RNA codon table (see picture), look for the animo acid that the mRNA, CAU, codes for. Remember the table is used for mRNA sequences, not tRNA sequences! The tRNA sequence is only used to attached to the mRNA when bringing in the amino acid. From the table you can see that CAU codes for His (Histidine).

The blanks are CAU, GUA, and His.

Apparently the correct answer is carbohydrates