B. The use of words such as "planetary" and "potential" helps establish a formal style.
Explanation:
In this excerpt, Al Gore's purpose is to capture the attention of the audience so that people understand the threats of global warming and pollution, so that they create conscience towards the behavior of humanity with the planet, and to take actions to solve the current problems. Al Gore's choice of words create a formal style to create an objective and precise impact on the audience's conscience.
