ACT Reading: Natural Science (Drill 3)

Question 1. The main argument of the passage is that:

• A) light pollution is primarily a human aesthetic problem caused by the loss of visible stars.
• B) artificial light at night disrupts the navigation and behavior of a wide range of organisms. ✓
• C) insects are more vulnerable to the effects of light pollution than any other animal group.
• D) conservation efforts have been largely successful in protecting sea turtles from artificial lighting.

Explanation: Choice B is correct. The passage systematically examines how artificial night lighting disrupts insects, sea turtles, and migratory birds, and concludes with a unifying explanation about biological signal systems. Choice A is explicitly contradicted by the opening paragraph, which states the disruption 'extends far beyond the loss of visible stars.' Choice C introduces a comparative claim about insects being 'most vulnerable' not made in the passage. Choice D overstates the success of conservation efforts; the passage describes responses, not victories.

Question 2. According to the passage, nocturnal insects such as moths use the moon and stars to:

• F) determine when to begin and end their activity each night.
• G) navigate by using them as directional references. ✓
• H) identify food sources in low-light environments.
• J) communicate with other members of their species.

Explanation: Choice G is correct. The passage states directly that moths and other nocturnal insects 'navigate using the moon and stars as directional references.' Choice F describes timing behavior (circadian rhythms), not navigation, and is not what the passage says about the moon and stars. Choice H introduces food identification as a use for celestial navigation, which the passage does not mention. Choice J introduces communication, which is not discussed in the passage.

Question 3. The passage most strongly suggests that sea turtle hatchlings are drawn inland by coastal lighting because:

• A) they mistake the warmth of road lights for the sun rising over the ocean.
• B) they are attracted to lights that are brighter than the reflected moonlight on the water, as the passage describes it.
• C) coastal lighting has replaced the natural brightness cue they use to navigate toward water. ✓
• D) their nests are increasingly being built in areas far from the ocean shoreline.

Explanation: Choice C is correct. The passage explains that hatchlings use 'the brightness of the open horizon, historically the moonlit ocean, to navigate toward water,' and that 'coastal lighting has reversed this cue,' drawing them toward lights on land instead of toward the sea. Choice A introduces heat/warmth as a factor not mentioned in the passage. Choice B partially describes the mechanism but misrepresents it, hatchlings follow the brighter cue, which has been redirected by artificial light, not simply overwhelmed by a brighter source. Choice D introduces nest location as a factor not discussed in the passage.

Question 4. As it is used in the passage, the word 'skyglow' refers to:

• F) the natural luminescence produced by the Milky Way galaxy.
• G) the brightening of the night sky caused by artificial light scattering off clouds and atmosphere. ✓
• H) the reflection of city lights on calm ocean or lake surfaces.
• J) a measurement scale used by astronomers to rate urban light pollution.

Explanation: Choice G is correct. The passage defines skyglow as the 'glow' created when 'urban light pollution scatters and reflects off clouds and atmospheric particles'; it is a diffuse brightening of the night sky over cities caused by artificial light. Choice F describes natural astronomical phenomena, not artificial light. Choice H describes a different reflective effect not mentioned in the passage. Choice J introduces a measurement scale that does not appear in the passage.

Question 5. The final sentence of the passage, 'The common thread across these cases is a mismatch between an ancient biological signal system and an environment that has changed faster than evolution can compensate', primarily functions to:

• A) suggest that all three species discussed will eventually adapt to artificial lighting.
• B) provide a unifying explanation for the disruptions described throughout the passage. ✓
• C) argue that human technological development should be slowed to allow evolution to keep pace.
• D) introduce a new scientific question that the passage has not yet addressed.

Explanation: Choice B is correct. The final sentence follows three separate case studies, insects, sea turtles, birds, and draws them together under a single explanatory framework: all three share the same fundamental problem of being biologically calibrated to signals that artificial light has overridden. Choice A suggests adaptation will occur, which the sentence does not claim and the passage does not support. Choice C draws a policy conclusion not made in the passage. Choice D incorrectly characterizes the sentence as introducing a new question; it synthesizes what has come before.