Three sentences are given, with one word highlighted in bold in each sentence. These words are to be replaced by one single word. Choose the word from the five options provided, which is grammatically and contextually correct.
I. It enables him to fix fleeting memories and to communicate with his fellows.
II. The primary focus will be on the act of measuring, with everything else receiving a rather cursory treatment.
III. The love is often transient , whilst the self-pity is more lasting.