Answer:
true
Step-by-step explanation:
The Earth’s climate and atmosphere have changed drastically over the last 4.5 billion years. Today’s global average temperature is around 59°F, but scientists estimate it has been as low as 10°F1 (during “snowball Earth” events) and as high as 95°F or above2 (so hot the Arctic North resembled today’s tropics). The atmosphere has changed too: Earth used to have very little oxygen, until the first cyanobacteria (or “blue-green algae”) showed up and started producing it. Today, oxygen is the second-most common element in the atmosphere.
But if we want to better understand how the Earth may respond to the rising levels of carbon dioxide (CO2) in the atmosphere that we’re experiencing today, we should look to a particular event around 56 million years ago