Answer Key: Central Idea and Evidence Across Two Texts

Full credit for any reasonable notice + prediction. Examples — Notice: "both titles are about the night sky / lights / stars." Predict: "both texts are about why we lose the stars and how to get them back," or "cities are turning off lights to see stars again." Any on-topic prediction is acceptable; no single answer is required.

Accept any answer showing that a topic is what the text is about (a word or short phrase, e.g., "light pollution"), while a central idea is the main point the writer makes about that topic, stated as a full sentence (e.g., "light pollution harms animals but is easy to fix"). Effort credit if the idea is close even if wording is rough.

From Text A, paragraph [1]: light pollution is the extra brightness that fills the sky when artificial lights from streets, signs, and buildings shine upward. Ideal: man-made lights pointing up into the sky. Accept any answer naming artificial/city lights aimed upward.

A defensible central idea for Text A: "Light pollution hides the stars and harms wildlife, but it is one of the easiest kinds of pollution to fix." Accept variations that capture the harm-and-easy-fix combination, or a narrower but accurate main point (e.g., "Light pollution is a problem we can undo by aiming lights down"). Supporting paragraph most often [3] (the fix) or [2] (the harm). Reject a bare topic word ("light pollution") or a single supporting detail treated as the whole idea.

A defensible central idea for Text B: "Cities are passing rules to cut light pollution because doing so brings back the stars, improves nighttime safety, and saves money." Accept variations that capture that communities act against light pollution and gain multiple benefits. Supporting paragraph [1] (ordinances), [2] (safety), or [3] (money). Reject a bare topic word or a single detail as the whole idea.

Reasonable inferences: city leaders are responsible for budgets, so a benefit that saves money is easier to justify than one that is mainly about beauty/stars; the money argument convinces even people who don't care about stargazing; saving on energy bills is a concrete, practical result that voters and officials value. Ideal: money is a practical reason that appeals to more decision-makers, so it "finally" tips the decision. This is an inference because the text does not state the reason outright. Accept any logical inference tied to the text.

7a — B. "Extra light disappears the instant a bulb is switched off or pointed downward." (Text A [3]) — this directly shows the fix is fast and simple.
Why the others are wrong: A describes a starry sky, not a fix; C describes harm to birds, not ease of fixing; D describes a result in one city but not why the problem is easy to fix. Only B states how quickly the light can be removed.
7b: Accept any sentence explaining that B shows the problem ends the moment a light is turned off or aimed down, so it is easy/fast to fix.

Agree (accept any shared idea with a paragraph from each): both texts agree that light pollution can be reduced by aiming lights downward / turning them off — Text A [3] ("pointed downward," shields) and Text B [1]–[2] (ordinances requiring lights to point down). Both also treat light pollution as a real, solvable problem.
Differ (accept any accurate contrast): Text A focuses on the effects on nature/wildlife (sea turtles, migrating birds — [2]) and on how easy the fix is; Text B focuses on what communities do about it and the added benefits of safety ([2]) and saving money ([3]). Award full credit for one valid agreement and one valid difference, each with a text + paragraph cited.

Acceptable shared central-idea statements (any one, or similar, stated as a full sentence):

• "Light pollution is a real problem, but people can reduce it by aiming lights down or turning them off."
• "Communities can bring back the night sky by changing how they use outdoor lights."
• "Cutting light pollution helps both the sky and the people below it."

Evidence locations — must include ONE from Text A and ONE from Text B:

• Text A [3] — "extra light disappears the instant a bulb is switched off or pointed downward"; or [2] harm to turtles/birds; or [1] artificial light causing the glow.
• Text B [1] — Flagstaff's dark-sky ordinance requiring lights to point down; or [2] shielded lights improving safety; or [3] shielded lights saving money.

Reasoning should connect both pieces of evidence to the shared central idea (e.g., both texts show that changing how lights are aimed reduces the problem and brings benefits). Full credit requires a defensible shared central-idea sentence + one correctly located piece of evidence from each text + reasoning that links them. Deduct if evidence comes from only one text (see misconceptions).

Articulate: accept any accurate one-sentence shared central idea in the student's own words (see Q9 list).
Connect: the cited sentence must actually match the stated central idea (e.g., Text A [3] "pointed downward," or Text B [1] the dark-sky ordinance).
Extend: any reasonable text-based action for a school or town (e.g., add shields to point streetlights/parking-lot lights down, use lower-power bulbs, turn off outdoor lights when not needed, pass a dark-sky rule). More than one answer is defensible.