Question 1Change answer

a)  What is the oldest 'Era' shown on this scale? 

Question 1Change answer

b)  What is the most recent 'Sub-era'?

Question 2Change answer

c)  How long did the Permian 'Sub-era' last?   million years 

Question 3Change answer

d)  A group of dinosaurs called Stegosaurs roamed the Earth between 188 and 65 million years ago.

d)  A group of dinosaurs called Stegosaurs roamed the Earth between 188 and 65 million years ago.

    What was the main 'Sub-era' they lived in?

Question 4Change answer

e)  What does the z stand for in the abbreviation Pz?

Question 5Change answer

f)  Why do scientists use abbreviations for time periods?

f)  Why do scientists use abbreviations for time periods?