Final answer:
The greatest challenge facing genome sequencing is developing fast and accurate sequencing techniques.
Step-by-step explanation:
The greatest challenge facing genome sequencing is the inability to develop fast and accurate sequencing techniques. While it is now relatively easy to obtain the entire genomic sequences of pathogens, sequencing the human genome is still a complex and time-consuming process. Advancements in sequencing technologies have reduced the speed and cost of sequencing the human genome, but further progress is needed to make sequencing more efficient and accessible.