LIFE SCIENCE

Detailed explanation-1: -As the RNA polymerase continues down the strand of DNA, more nucleotides are added to the mRNA, thereby forming a progressively longer chain of nucleotides (Figure 2). This process is called elongation. Figure 3: DNA (top) includes thymine (red); in RNA (bottom), thymine is replaced with uracil (yellow).

Detailed explanation-2: -Elongation. Finally, elongation–the addition of nucleotides to the new DNA strand–begins after the primer has been added. Synthesis of the growing strand involves adding nucleotides, one by one, in the exact order specified by the original (template) strand.

Detailed explanation-3: -Transcription is the first step of gene expression and involves RNA polymerases. After transcription initiation, RNA polymerase enters elongation followed by transcription termination at the end of the gene.