Question

when the sky turned red and green
physical science studies: relationships of force and motion
on the night of october 24, 2011, people in several states were treated to a rare event. the dark sky glowed red and sometimes green. it was as if someone were putting on a light show. in fact, this was a show of nature called an aurora borealis. a powerful solar storm had generated colorful northern lights. these reached unusually far south. they could be seen in arkansas, alabama, georgia, and kentucky.

orthern lights are very rare events,\ said nasa scientist bill cooke. \we dont see them this far south that often.\
an aurora begins many hours after a storm on the sun produces
photo credit and all related images: ap/weather.com/brian emfinger
in october 2011, the northern lights showed up farther south than they usually do.
the text below is on a green background
the question is: why did the author include this passage?
the passage referred to is about how an aurora occurs: made up of charged particles. these are mostly electrons and protons. as the burst of solar wind passes earth, it slams into earths magnetic field. that triggers electrons to flow toward earths north and south poles......there, they hit atoms of oxygen and nitrogen gas. this eventually releases energy, which produces the colorful lights of an aurora.
the options are:
a. to suggest that the colorful lights of an aurora are not to be missed
b. to explain why an aurora borealis is more dangerous than a tornado
c. to explain what a magnetic field is
d. to describe what an aurora is and how it occurs

Explanation:

The passage in the green box describes the composition of an aurora (made of charged particles like electrons and protons) and the process of how it occurs (solar wind hitting Earth's magnetic field, electrons flowing to poles, hitting gas atoms, releasing energy as light). Option A is incorrect as the passage doesn't suggest lights were missed. Option B is incorrect as there's no comparison to tornado danger. Option C is incorrect as the passage doesn't explain what a magnetic field is (it just mentions it in the process). Option D matches as it describes what an aurora is (made of charged particles) and how it occurs (the steps of solar wind, magnetic field, electron flow, hitting gas atoms, energy release as light).

Answer:

D. To describe what an aurora is and how it occurs