Question
Read the excerpt about ozone from a NASA publication.
“Ozone is a gas . . . [that] occurs naturally in small (trace) amounts in the upper atmosphere. . . . Ozone protects life on Earth from the Sun’s ultraviolet (UV) radiation. . . . Near the Earth’s surface, ozone is created by chemical reactions between air pollutants from vehicle exhaust, gasoline vapors, and other emissions. At ground level, high concentrations of ozone are toxic to people and plants.”
—NASA Ozone Hole Watch
Which statement best summarizes the main idea being expressed?
(1 point)
Responses
A Ozone needs to be at high levels throughout the atmosphere because people and plants need it to live.
B Ozone is toxic, so its presence in the atmosphere is dangerous for the environment.
C Ozone levels can rise or fall without significantly affecting people or the environment.
D Ozone is necessary high in the atmosphere but dangerous in the lower atmosphere.