1．(2019·全国卷Ⅰ)Itisdifficulttofigureoutaglobalpopulationofpolarbearsasmuchoftherangehasbeen____________(poor) studied.
2．(2019·全国卷Ⅰ)Scientistshaverespondedbynotingthathungrybearsmaybecongregating(聚集) aroundhumansettlements, leadingtotheillusion(错觉) thatpopulationsare____________(high) thantheyactuallyare.
