Which geologic event is associated with the end of the Paleozoic Era?

The end of the Paleozoic Era is marked by the largest mass extinction event in Earth's history, known as the Permian-Triassic extinction event. This event occurred approximately 252 million years ago and is estimated to have led to the extinction of about 90 to 96 percent of all marine species and a significant number of terrestrial organisms.

This catastrophic reduction in biodiversity is believed to have been caused by a combination of factors, including intense volcanic activity, climate change, and changes in sea level. The consequences of such a massive extinction reshaped the course of life on Earth, paving the way for the Mesozoic Era and the subsequent emergence of dinosaurs and other new forms of life.

The other choices reflect important geologic processes and events but do not specifically correlate with the end of the Paleozoic Era. For example, the formation of coal deposits occurred during various periods of the Paleozoic, particularly in the Carboniferous. The Himalayas began forming much later, during the collision of the Indian and Eurasian plates, which is a Mesozoic event. Continental drift is a continuous process that has been occurring over millions of years and is not tied to a specific endpoint of an era.