Explanation

The sentence implies that Canada’s invertebrates and plants have not yet been assessed, so the assessment of Canada’s biodiversity is not finished; therefore, the correct answer to Blank (i) is “complete.” The assessment of invertebrates and plants is described as a “challenge,” so the answer to Blank (ii) must be synonymous with “difficult.” The only answer choice that matches this meaning is “daunting,” so it is correct. Thus the correct answer is complete (Choice B) and daunting (Choice F).
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For the second blank why can't daunting be the answer as a high number of species, each requiring a different approach, cannot be a repetitious task

Sorry,

I have fixed the OA that indeed is daunting as you pointed out.

Notice That in the second reply of this thread AKA the official explanation the answers were right: B and F. In the spoiler the second blank was wrong.

Anyhow, Thank you so much.
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