Question

a. it will be easy to turn the clock back and restore dark night skies. b. people no longer value being able to see the stars at night. c. dark night skies are an unrecoverable loss for humanity. d. the change to the night skies has happened recently and rapidly. what does it mean in paragraph 4 that \light pollution is the culprit\?

Explanation:

1. Analyze option A: There is no indication in the context that turning back the clock and restoring dark - night skies is easy.
2. Analyze option B: The text doesn't suggest that people no longer value seeing stars at night.
3. Analyze option C: There is no evidence to support that dark - night skies are an unrecoverable loss for humanity.
4. Analyze option D: The change to night skies due to light pollution has occurred recently and rapidly as a result of human activities related to lighting.

Answer:

D. The change to the night skies has happened recently and rapidly.