According to the video, what is the main criterion for defining a geological epoch?

Significant environmental changes that are recorded in Earth's rock layers.

Name two specific examples of how nuclear weapons have impacted the geological record, as mentioned in the video.

Spread of radionuclides and synthetic isotopes like Plutonium 239.

It causes a decrease of certain carbon isotopes, like Carbon-13.

I can describe how humans change their environment by building different structures.

1
The Geologic Time Scale is divided into eons, eras, periods, epochs, and ages, based on major environmental changes.
2
Burning fossil fuels releases CO₂ and decreases certain carbon isotopes, which will be detectable in fossilized remains.
3
Humans have transformed over 50% of the Earth’s land area through deforestation, farming, mining, dams, and modifying coastlines, affecting sediment layers.