Meaning: Injured means harmed or damaged, referring to body parts that have sustained some form of injury.

Wrong options:

• active: Active is an adjective that describes something currently in action, which does not fit the context of describing body parts that are in a state of harm.
• injures: Injures is a verb form that does not fit grammatically as it would require a subject performing the action, rather than describing the state of the body parts.
• actively: Actively is an adverb that modifies verbs, not suitable here as it does not describe the state of the body parts.

Correct answer: sophisticated

Explanation: The word 'sophisticated' is an adjective that appropriately describes the advanced nature of the sensory capacities of octopuses. It fits grammatically and contextually, indicating a high level of complexity in their sensory abilities.

Meaning: Sophisticated means having a high degree of complexity or refinement, indicating that octopuses possess advanced sensory abilities.

Wrong options:

• lackluster: Lackluster means lacking in vitality or brilliance, which contradicts the idea of octopuses having advanced sensory capacities.
• civilized: Civilized refers to a state of social development, which does not apply to sensory capacities and is contextually irrelevant here.
• vapid: Vapid means lacking flavor or interest, which is the opposite of what is intended in describing the sensory capacities of octopuses.

Correct answer: complex

Explanation: The word 'complex' fits grammatically as an adjective that describes the behavior of octopuses. It aligns contextually with the idea that their behavior is intricate and multifaceted, contributing to the certainty of their rich subjective experience.

Meaning: Complex means consisting of many different and connected parts, indicating that octopus behavior is not simple but rather intricate.

Wrong options:

• rude: Rude describes a lack of manners or politeness, which is irrelevant to the context of octopus behavior.
• ignorant: Ignorant means lacking knowledge or awareness, which does not apply to the description of behavior and is contextually inappropriate.
• benighted: Benighted refers to being in a state of moral or intellectual darkness, which does not fit the context of describing behavior.

Correct answer: complicated

Explanation: The word 'complicated' is an adjective that accurately describes the nature of the question regarding the subjective experience of an octopus. It fits grammatically and contextually, indicating that the relationship between the brain and body adds layers of difficulty to understanding their experience.

Meaning: Complicated means consisting of many interconnecting parts or difficult to analyze, suggesting that understanding an octopus's subjective experience is not straightforward.

Wrong options:

• evident: Evident means clear or obvious, which contradicts the idea that the relationship is difficult to understand.
• explained: Explained is a verb form that does not fit grammatically as it does not describe the state of the question itself.
• delineated: Delineated means described or portrayed, which does not capture the complexity implied in the relationship between the brain and body.