Answer:
I would say around the 11th or 12th hour
Step-by-step explanation:
seeing as the question calls for ALL of earth's history compressed into 12 hours the timeline should be similar to this: Earth was born at midnight, at around 2-3 AM land masses form, Right after that, life begins, For around 8 hours (11 PM) life is confined in water, right after that we have plants, 22 minutes later we have dinosaurs, 22 minutes later we have mammals, 5 minutes later dinosaurs are extinct, 6 minutes later we have people. So it's most likely the 12th hour. I hope this helps.