transcription is the process of copying genetic information from one strand of DNA into RNA based on the principle of complementarity . A critical rule in this process is that Adenosine (A) in the DNA template strand pairs with Uracil (U) in the mRNA, while Thymine (T) pairs with Adenine (A), and Guanine (G) pairs with Cytosine (C) . For the given DNA sequence ATACG, the complementary mRNA sequence is calculated as follows: A→U, T→A, A→U, C→G, and G→C, resulting in UAUGC. Mastering these biochemical pairing rules is essential, as NCERT textbooks are the primary source for approximately 95% of NEET Biology questions .