It is the Mid-Atlantic Ridge.
I assume your are talking about Ursa Major and Ursa Minor, the constellations. Ursa Major has 21 visibly bright stars and Ursa Minor has 7. So there is a 14 star difference. Hope this helps!
Answer:
C. At least five mass-extinction events have occurred during the last 500 million years.
Explanation:
- The history of mass extinct is related to the five mass extinctions that are caused over by the 350 million years n which many species have disappeared in there short geologic time.
- A massive extinction is caused in the Permian Triassic extinction event i.e about 250 mn years ago which on an estimate has killed 90% of the species.
- The Cretaceous–Paleogene extinction event that occurred over 66 million years ago is known to have wiped out the dinosaurs and many other species.