Meaning: 'Ideal' refers to the most suitable or perfect conditions for something, in this case, life.

Wrong options:

• ideally: 'Ideally' is an adverb that describes how something should be done, which does not fit as it does not modify 'place.'
• actually: 'Actually' is an adverb that indicates a fact or reality, but it does not describe the suitability of a place.
• whereas: 'Whereas' is a conjunction used to contrast two statements, which does not fit in this context as it does not describe a place.
• thus: 'Thus' is an adverb indicating a conclusion or result, which does not fit as it does not describe a place.

Correct answer: Virtually

Explanation: The term 'Virtually' serves as an adverb that indicates almost all of the information comes from Galileo, fitting the context of the sentence perfectly.

Meaning: 'Virtually' means nearly or almost, indicating that the information is predominantly from one source.

Wrong options:

• ideally: 'Ideally' is an adverb that describes how something should be, which does not fit the context of providing information.
• actually: 'Actually' is an adverb that indicates a fact, but it does not convey the sense of near completeness required here.
• whereas: 'Whereas' is a conjunction used to contrast two statements, which does not fit in this context as it does not provide information about the source.
• thus: 'Thus' is an adverb indicating a conclusion or result, which does not fit as it does not describe the extent of information.

Correct answer: Although

Explanation: The word 'Although' is a conjunction that introduces a contrast, setting up the sentence to discuss the general perception of Europa versus the findings of researchers, making it contextually appropriate.

Meaning: 'Although' is used to introduce a statement that contrasts with what has been previously mentioned.

Wrong options:

• ideally: 'Ideally' is an adverb that describes how something should be done, which does not fit as it does not introduce a contrast.
• actually: 'Actually' is an adverb that indicates a fact, but it does not serve to contrast two ideas.
• whereas: 'Whereas' is a conjunction that also indicates contrast, but it does not fit as smoothly in this context as 'Although.'
• thus: 'Thus' is an adverb indicating a conclusion or result, which does not fit as it does not introduce a contrasting statement.

Correct answer: recent

Explanation: The word 'recent' is an adjective that describes the noun 'measurements,' indicating that the measurements are the latest available, which fits the context of the sentence discussing new findings.

Meaning: 'Recent' refers to something that has happened or been done not long ago, in this case, measurements.

Wrong options:

• ideally: 'Ideally' is an adverb that describes how something should be done, which does not fit as it does not describe measurements.
• actually: 'Actually' is an adverb that indicates a fact, but it does not describe the timing of the measurements.
• whereas: 'Whereas' is a conjunction used to contrast two statements, which does not fit in this context as it does not describe measurements.
• thus: 'Thus' is an adverb indicating a conclusion or result, which does not fit as it does not describe the timing of measurements.

Correct answer: however

Explanation: The word 'however' is an adverb that introduces a contrast to the previous statement about the findings, indicating that despite the evidence, there is still uncertainty, making it contextually appropriate.

Meaning: 'However' is used to introduce a statement that contrasts with or seems to contradict something that has been said previously.

Wrong options:

• ideally: 'Ideally' is an adverb that describes how something should be done, which does not fit as it does not introduce a contrast.
• actually: 'Actually' is an adverb that indicates a fact, but it does not serve to contrast the findings with the uncertainty.
• whereas: 'Whereas' is a conjunction that indicates contrast, but it does not fit as smoothly in this context as 'however.'
• thus: 'Thus' is an adverb indicating a conclusion or result, which does not fit as it does not introduce a contrasting statement.