Select the correct answer from the list.(1 point)
Between 400,000 years ago until 1950, the levels of carbon dioxide in the atmosphere never exceeded _____ parts per million. Today, carbon dioxide levels have exceeded
________ parts per million.
The correct answer is:
400; 400
what is TRUE and FALSE
climate has changed naturally over earths history
the increase in carbon dioxide scince the year 1860 is similar to past increses
earth is currently in an interglacial period
atmospheric composition has remained constant
The correct answers are:
1. TRUE
2. FALSE
3. TRUE
4. FALSE
Earth's most recent glacial period ended about _________ area years ago.
The Great Oxygenation Event began about ______ area years ago.
About __________ area years ago carbon dioxide began increasing exponentially to unprecedented levels.
fill in with 2.3 billion 11,500 160
Earth's most recent glacial period ended about 11,500 area years ago.
The Great Oxygenation Event began about 2.3 billion years ago.
About 160 area years ago carbon dioxide began increasing exponentially to unprecedented levels.