Approximately how many genes are present in the human genome?

• A. ~20,000
• B. ~30,000
• C. ~24,000
• D. ~40,000

Answer: (C)

The question is probing how many genes the human genome contains. Gene counting depends on what you include as a gene (protein-coding genes and various noncoding RNA genes), and the numbers reported have shifted a bit with newer annotations. A widely cited figure for the number of genes in humans sits in the 20,000 to 25,000 range, with about 24,000 often used as a representative total. That makes about 24,000 the best fit among the options because it lands right in the commonly cited ballpark.

The other numbers are further from the typical annotated gene counts: around 20,000 is plausible for protein-coding genes, but including noncoding RNA genes pushes the total higher, and 30,000 or 40,000 would be considered overestimates given standard annotations.