Final answer:
Humans have existed for a very small percentage of Earth's history.
Step-by-step explanation:
The approximate percentage of geologic time that humans have existed on Earth since its origin is extremely small. Earth is approximately 4.6 billion years old, and humans have only been around for a fraction of that time. If we were to think of Earth's history as a 24-hour day, humans would have appeared only during the last minute of that day.