问题详情

Why does the professor begin the lecture by describing the destructive force of an asteroid impact？
A．To illustrate the violent conditions present on the early Earth.
B．To support an explanation for mass extinctions in Earth"s history.
C．To imply that human activities are threatening the planet.
D．To emphasize the short timeframe. of extinction events.请帮忙给出正确答案和分析，谢谢！