Answer:
2. Gene
3. DNA
1. Pre-mRNA
4. mRNA
Explanation:
Transcription is the first step of gene expression in which a DNA molecule serves as template for the synthesis of mRNA. In the process of transcription, a Gene present on the DNA molecule is transcribed by RNA polymerase using complementary base pairing rule.
After the gene is transcribed, a pre-mRNA is formed. This mRNA is so called because it is immature. The pre-mRNA undergoes processing such as polyadenylation, splicing etc. to become a mRNA.
Hence, based on this, the order is:
Gene → DNA → pre-mRNA → mRNA
