Meaning: 'Times' refers to specific periods or eras in history, indicating that the hippopotamus has been known throughout various historical periods.

Wrong options:

• era: The word 'era' is singular and implies a distinct period, which does not fit well with the plural context of 'ancient' in this sentence.
• age: While 'age' can refer to a period, it is often used in a more general sense and does not convey the same historical specificity as 'times.'
• years: 'Years' refers to a unit of time rather than a period in history, making it less suitable in this context.

Correct answer: well

Explanation: The word 'well' is an adverb that appropriately describes how hippos are adapted to aquatic life, indicating a high degree of suitability. It fits grammatically and contextually, as it modifies the verb 'adapted' effectively.

Meaning: 'Well' means in a good or satisfactory manner, indicating that hippos are highly suited for life in water.

Wrong options:

• poorly: 'Poorly' suggests a lack of suitability, which contradicts the intended meaning of the sentence regarding hippos' adaptation.
• nice: 'Nice' is an informal term that does not accurately convey the degree of adaptation required in this context.
• too: 'Too' implies excess and does not fit grammatically or contextually as it does not modify 'adapted' appropriately.

Correct answer: dense

Explanation: The word 'dense' fits grammatically and contextually as it describes the physical characteristic of the hippo's body, indicating that it is heavy and compact, allowing them to walk underwater. It aligns with the sentence structure and meaning.

Meaning: 'Dense' means closely packed together, indicating that the hippo's body is heavy enough to allow it to walk underwater.

Wrong options:

• variable: The word 'variable' suggests changeability, which does not apply to the consistent physical characteristic of the hippo's body in this context.
• refined: 'Refined' implies a level of sophistication or purity, which does not accurately describe the hippo's physical attributes.
• rigid: 'Rigid' suggests inflexibility, which does not accurately convey the nature of the hippo's body in relation to its ability to move underwater.

Correct answer: dips

Explanation: The word 'dips' fits grammatically and contextually as it refers to short immersions in water, which is necessary for hippos to stay hydrated. It aligns with the overall meaning of the sentence regarding their need for water.

Meaning: 'Dips' refers to brief immersions in water, indicating that hippos need to periodically enter water to prevent dehydration.

Wrong options:

• tips: 'Tips' does not relate to hydration or water immersion, making it contextually irrelevant in this sentence.
• sips: 'Sips' implies small amounts of drinking, which does not convey the action of entering water as effectively as 'dips.'
• naps: 'Naps' refers to short sleeps and does not relate to hydration or the need for water, making it unsuitable in this context.