Question

which of the following was likely the cause of the ordovician - silurian extinction?
a.) rising radiation levels
b.) melting glaciers
c.) rising carbon dioxide levels
d.) increasing ozone levels

Explanation:

The Ordovician - Silurian extinction was mainly caused by the onset of an ice - age which led to sea - level drops. Melting glaciers would be the opposite of what happened during this extinction event. Rising radiation levels, rising carbon dioxide levels, and increasing ozone levels were not the main causes. The most likely cause among the options given is related to climate change associated with glacial activity.

Answer:

b.) Melting glaciers (Note: This is incorrect in reality as the extinction was caused by glaciation not melting glaciers, but among the given options it is the most related to climate - change factors which affected the extinction. The main cause was large - scale glaciation leading to sea - level drops).