For centuries, darkness shaped the rhythms of both human and animal life. Today, however, artificial lighting has spread so widely that true...

For centuries, darkness shaped the rhythms of both human and animal life. Today, however, artificial lighting has spread so widely that true darkness is becoming rare. The result is not just a brighter world, but ecological disruption. Migrating birds, nocturnal insects, and marine species that rely on natural light cues (18) __________, often with effects that extend far beyond a single habitat.

Humans, too, are not exempt from these effects. Although artificial light is commonly associated with safety, comfort and economic activity, the body does not simply ignore prolonged exposure to it. (19) __________. Researchers have linked excessive nighttime illumination to poorer sleep quality, hormonal disruption and reduced overall well-being, especially in densely populated urban areas.

Individuals illuminate homes, advertisers flood streets with visual stimuli, and local authorities often prioritize visibility over restraint, (20) __________ that constant brightness is associated with safety and progress. Critics may be tempted to blame urban expansion alone, (21) __________. The difficulty, then, lies not only in regulating excessive lighting, but also in questioning the assumptions that make constant brightness seem both normal and desirable. (22) __________.

[Adapted from a range of environmental commentaries]

Question 18:

A. are increasingly being drawn away from essential patterns of movement and behaviour

B. have increasingly drawn away essential patterns of movement and behaviour from themselves

C. increasingly draw themselves away from essential behaviour to seek artificial brightness

D. and which are increasing their movement and behaviour away from essential patterns

Question 19:

A. A growing body of evidence suggests that the human nervous system continues to register light as a biological signal

B. The human nervous system, suggesting a growing body of evidence, continues to register biological light as a signal

C. That the human nervous system continues registering light is a body of evidence growing as a biological signal

D. A biological signal is what the human nervous system continues registering because evidence has grown

Question 20:

A. strengthening the belief which many urban residents rarely question it

B. all of which strengthen the belief many urban residents rarely question

C. the belief many urban residents rarely question is strengthened by all

D. strengthening the belief many urban residents rarely question for their safety

Question 21:

A. whereas the truth is that everyday habits also play a substantial part in sustaining the problem

B. while everyday habits are substantial truths in the part they play to sustain the problem

C. but the truth of everyday habits substantially plays a part in sustaining the problem

D. since everyday habits are the truth that plays a substantial part of the problem

Question 22:

A. Until that cultural preference is challenged, technical solutions alone are unlikely to solve the issue

B. Since the issue is unlikely to be solved, technical solutions alone challenge that cultural preference

C. Technical solutions alone are unlikely, until the issue solves that cultural preference by challenge

D. Unless the issue is solved technically, that cultural preference alone is unlikely to be challenged