This three-blank question rewards careful reading of each clause.

Blank (i): The sentence argues that even someone not paying close attention would notice the historical difference in fish abundance. This is a rhetorical device lowering the bar — even the most casual (inattentive, uninterested) observer would see it. Using “prescient” (having foresight) or “clearheaded” would raise the bar rather than lower it, weakening the rhetorical effect.

Blank (ii): The passage envisions the past ocean as healthy and full. So those formerly abundant marine mammal species would appear plentiful (abundant, numerous). “Threatened” implies danger, contradicting the image of a healthy past ocean, and “unfamiliar” does not fit the logic.

Blank (iii): Without the magic glasses, we cannot easily perceive or recognize the difference between past and present oceans. Discern means to perceive or recognize clearly — perfect. “Ignore” and “dismiss” imply active rejection, not the passive difficulty of perception described.

Correct Answers: Blank (i) = A (casual), Blank (ii) = E (plentiful), Blank (iii) = H (discern).

Cultural shock is a significant barrier to communication. It refers to the anxiety, disorientation, and communication breakdown that occurs when individuals are suddenly immersed in a cultural environment whose norms, values, and expectations differ radically from their own. It is not merely “excitement” or “curiosity” — it is a genuine psychological stress response. The textbook illustrates this with examples like families from conservative Muslim cultures moving to Western countries, where gender mixing in schools, co-educational institutions, and different social norms create communication crises. Cultural shock is distinct from acculturation (Option D), which is the gradual, successful adaptation to a new culture. Cultural shock is the resistance to or inability to adapt, resulting in a failure of communication at the most basic level.