Question 5·Medium·Central Ideas and Details
The passage below is from a recent op-ed about the effects of artificial light at night.
City lights once symbolized progress, but their glow now stretches far beyond the sidewalks they were meant to illuminate. Satellite images show halos of brightness bleeding into deserts and oceans, marking where turtles lose their way and migrating birds drop exhausted. Even the ordinary house sparrow sings earlier than it should, tricked by a dawn that never truly arrives. We do not set out to sabotage the rhythms of other creatures; we simply forget that darkness is also a resource, as precious and finite as clean air. Until we learn to budget light as carefully as we budget water, we will continue to spend the night sky into debt.
Based on the passage, what main claim does the author make about artificial light at night?
For main claim or central idea questions, first read the entire short passage, then quickly restate in your own words: "What is the author mainly saying about this topic, and what do they want the reader to think or do?" Pay special attention to the first and last sentences, plus any repeated ideas or strong images. Then go to the choices and eliminate any that (1) contradict the passage’s tone, (2) focus on a minor detail instead of the overall message, or (3) introduce new ideas not mentioned in the text. Choose the option that best matches your own summary without adding or changing anything.
Hints
Check the overall attitude toward artificial light
Is the author praising artificial light, criticizing it, or just neutrally describing it? Look for contrast words like "but" and for emotionally loaded words or images.
Focus on the examples with animals
Pay close attention to what happens to turtles, migrating birds, and house sparrows. Are these examples showing benefits, harms, or something else?
Study the last two sentences
What does the author say about darkness being a "resource" and about learning to "budget light"? Ask yourself whether the author is suggesting a change in behavior or simply accepting the current situation.
Eliminate choices that add new ideas
Cross out any answer choices that bring in topics the passage never mentions, such as money costs or whether change is impossible.
Step-by-step Explanation
Identify the general topic and tone
Read the first sentence: "City lights once symbolized progress, but their glow now stretches far beyond the sidewalks they were meant to illuminate."
The topic is city/artificial lights at night, and the word "but" signals a contrast: the author is moving from a positive past view (progress) to a present concern. The overall tone is worried or critical, not positive or neutral.
Notice the specific effects described
Look at the middle sentences: "halos of brightness" are "marking where turtles lose their way and migrating birds drop exhausted." Even house sparrows "sing earlier than [they] should," "tricked by a dawn that never truly arrives."
These details show that nighttime light is confusing and harming wildlife and disrupting natural rhythms. This is an ecological problem (it affects animals and nature).
Understand the idea of "unintended" and "resource"
The author says, "We do not set out to sabotage the rhythms of other creatures; we simply forget that darkness is also a resource, as precious and finite as clean air."
This means humans are not trying to hurt animals (so the harm is unintentional), but by ignoring the value of darkness, we end up doing damage. Darkness is being treated like something valuable that we should protect and manage.
Look for a call to action in the conclusion
The last sentence gives the author's recommendation: "Until we learn to budget light as carefully as we budget water, we will continue to spend the night sky into debt."
This is a clear call to action. The author wants society to "budget" or manage artificial light more carefully, just as we manage water. That means people should do something to fix the problem, not just accept it.
Match the main idea to the answer choices
Combine what you found: artificial light at night is unintentionally harming animals and natural cycles, and the author urges us to manage ("budget") light more carefully.
Choice B, "It has unintended ecological consequences that society must address," best captures both parts: the unintentional harm to nature and the need for humans to take action. Therefore, the correct answer is B) It has unintended ecological consequences that society must address.