Darwin's Work Tense Analysis

The sentence requires appropriate verb tenses to describe a historical event and its influence.

Blank (i): Verb Tense Selection

• The subject is "Darwin's work", a singular noun referring to a completed historical action.
• A past tense verb is needed to reflect this historical context.
• The verb options are 'have', 'had', 'has'.
• 'had' is the simple past tense form, fitting the context of Darwin's historical work.
• Thus, 'had' is the correct choice for the first blank (i).

Blank (ii): Verb Tense Selection

• This blank relates to the effect caused by Darwin's work and how it influenced environmental politics.
• The structure is "...effect that (ii)_______ influenced...". The subject is the singular 'effect'.
• The present perfect tense ('has influenced') is appropriate here. It connects a past action (the influence) to its continuing relevance or result in the present development of environmental politics.
• Thus, 'has' is the correct auxiliary verb for the second blank (ii).

Complete Sentence

Combining the correct tenses gives:

Darwin's work had a related effect that has influenced the development of environmental politics – a ‘decentering' of the human being.

This matches the combination (i) had and (ii) has.