Meaning: 'In the past' refers to a time before the present, indicating that the exploitation happened previously.

Wrong options:

• in the future: This phrase indicates a time yet to come, which contradicts the context of past damage.
• ever before: This phrase is awkward in this context and does not clearly indicate a specific time frame relevant to the damage done.
• on one side: This phrase suggests a spatial relationship rather than a temporal one, making it irrelevant to the context.

Correct answer: while

Explanation: The word 'while' introduces a contrast between two simultaneous actions, indicating that development efforts are happening at the same time as caring for the environment. This fits grammatically as a subordinating conjunction linking two clauses.

Meaning: 'While' means during the time that; at the same time as, suggesting simultaneous actions.

Wrong options:

• whereas: This word indicates a contrast but does not imply simultaneous actions, making it less suitable here.
• even: This word does not fit grammatically as it does not connect the two clauses appropriately in this context.
• though: This word suggests a concession but does not effectively link the two actions as 'while' does.

Correct answer: Because

Explanation: The word 'Because' introduces a reason for the statement that follows, fitting grammatically as a subordinating conjunction that explains why the Antarctic is largely undamaged.

Meaning: 'Because' means for the reason that, indicating causation.

Wrong options:

• Whether: This word introduces alternatives rather than a reason, making it unsuitable for the context.
• Unless: This word implies a condition that must be met, which does not fit the explanatory nature of the sentence.
• Besides: This word adds information but does not provide a causal relationship, making it inappropriate here.

Correct answer: already been discovered

Explanation: The phrase 'already been discovered' correctly uses the present perfect passive voice to indicate that the discovery has occurred at some unspecified time before now, fitting grammatically and contextually with the ongoing discussion of environmental issues.

Meaning: 'Already been discovered' means that the discovery has taken place prior to the present moment.

Wrong options:

• yet discovered: This phrase suggests that the discovery has not occurred, which contradicts the context of the sentence.
• ever discovered: This phrase is awkward and does not fit the grammatical structure needed here, as it implies a question of time rather than a statement of fact.
• already been discovering: This phrase incorrectly uses the present perfect continuous tense, which does not fit the context of a completed action.

Correct answer: banned

Explanation: The word 'banned' is the correct past participle that indicates a prohibition on exploitation, fitting grammatically as it completes the passive construction 'have been banned.'

Meaning: 'Banned' means officially or legally prohibited, indicating that exploitation would not be allowed.

Wrong options:

• expanded: This word suggests an increase or growth, which does not fit the context of prohibition.
• spanned: This word implies coverage over an area, which is irrelevant to the context of banning exploitation.
• transformed: This word suggests a change in form or appearance, which does not align with the idea of prohibition.