Alternative splicing primarily contributes to transcript diversity by

• A. Increasing transcription rate
• B. Allowing different combinations of exons to be included
• C. Editing nucleotide bases of exons
• D. Removing exons permanently

Answer: (B)

Alternative splicing expands transcript diversity by allowing different combinations of exons to be included in the final mRNA from a single gene. The spliceosome can join exons in various arrangements or use alternative splice sites, producing multiple mRNA variants—and often protein isoforms—with different combinations of functional domains. This increases the variety of transcripts without changing how much a gene is transcribed. It’s a post-transcriptional process; it doesn’t edit nucleotide bases (that would be RNA editing) and it doesn’t permanently remove exons from the genome—exons can be included or skipped in different contexts, giving diverse transcripts rather than a single, fixed sequence.