Which was the longest period of human existence on this planet

Human being as we know it now (homo sapien), between 100 et 200 thousand years old.

First from which we've evolved from, about 7 million year ago (australopithecus)

Lucy the oldest ancestor of the human race was alive 7 million years ago but she was not exactly human yet. Actual humans have been around for 500,000 years

From when we first evolved until now. There's only been one period of human existence.

The stone age. It lasted approximately 90,000 years, about 85-95% of the total human experience on this planet.

A