Read the text and mark the correct letter A, B, C or D for each question below

About 200 million years ago, as the Triassic Period came to a close, many species of animals disappeared from the face of the Earth. Scientists previously believed that the series of extinctions happened over a period of 15 to 20 million years. Recent discoveries in Nova Scotia 5 suggest, however, that the extinctions may have happened over a much shorter period of time, perhaps less than 850,000 years.

Evidence for a rapid extinction of species at the end of the Triassic Period is found in the McCoy Brook Formation along the Bay of Fundy 10 in Nova Scotia. Fossils found in this formation indicate a rapid disappearance of species rather than a slow and gradual change over time. One explanation for a relatively sudden extinction at the end of the Triassic may be that a large meteorite struck the earth at the time and is responsible for a 70- kilometer hole nearby. If geologists 15 and other researchers can find evidence, such as shocked quartz in the rock formations, that a meteorite did strike the earth, it would give more credence to the theory of rapid Triassic extinctions. It is possible, however, that even if a rapid extinction happened in and around Nova Scotia, it did not necessarily occur in the rest 20 of the world.

What is the main topic of this passage?

• A. 
  the disappearance of animal species at the end of the Triassic Period
• B. 
  evidence of a relatively sudden extinction of species
• C. 
  the possibility of an extinction happening simultaneously throughout the world.
• D. 
  a meteorite hole in the Bay of Fundy in Nova Scotia.