What is the main point Engels is making in this passage?

In relation to the september 11th attacks, the term ground zero refers to new york city. the pentagon. the shanksville, pennsylvania, memorial. the site of the world trade center.r

This pie chart shows statistics related to the world's population. a pie chart like this one is most for making predictions about the future. showing how parts make up a whole. presenting amounts over a period of time. comparing information from different sources.

Historians sometimes rely on video recordings in researching past events because