Geologic Time

The Earth is ​ (a)   years old

• 4.6 Billion
• 4.5 Billion
• 3.23456

Groups:

(a) Longest

,

(b) 2nd longest

,

(c) 3rd longest

,

(d) Shortest

• Epochs

• Eons

• Eras

• Periods

The​ (a)   accounts for 88% of Earth's history.

• Precambrian
• Photosyntheses
• Triassic

​ (a)   is added to the atmosphere by​ (b)   .

• Oxygen
• photosynthesis
• CO2
• burning fuel
• respiration

Rapid diversification of life during the Paleozoic is called the​ (a)  

• Cambrian Explosion
• diversification rapidus
• atomic bomb

Dinosaurs were dominant during the ​ (a)   .

• Mesozoic
• paleozoic

The largest mass extinction is the​ (a)   extinction

• Permian triassic
• asteroid from 66 million years ago

Non-avian dinosaurs became extinct due to ​ (a)  

• an asteroid impact
• flying too close to the Sun
• bad deodorant

The ​ (a)   is known as the age of ​ (b)   .

• Mammals
• Cenozoic
• Paleolithic
• dinosaurs

​ (a)   measures radioactive decay to date ancient rocks.

• Radiometric dating
• Relative dating