Question: A deep-sea researcher collects 9 extremophile microorganisms near a hydrothermal vent, including 4 thermophiles, 3 psychrophiles, and 2 barophiles. If the researcher sequences DNA samples in a lab dish by selecting one organism per day for 9 consecutive days, with organisms of the same type indistinguishable, how many distinct sequencing orders are possible? - go-checkin.com