Final answer:
The grammatical name is gerund. Synonyms for (i) careers: occupations, (ii) vehemently: intensely, (iii) assumed: presumed, (iv) despised: detested.
Step-by-step explanation:
The grammatical name given to the expression 'Chief Dende's death opened his eyes' is a gerund phrase. A gerund is a verb form that functions as a noun. In this case, the gerund phrase 'Chief Dende's death' is acting as the subject of the sentence.
(i) Another word that can replace 'careers' is 'occupations'. Both words refer to the work or profession that someone is engaged in.
(ii) Another word that can replace 'vehemently' is 'intensely'. Both words imply a strong and passionate manner of speaking or acting.
(iii) Another word that can replace 'assumed' is 'presumed'. Both words mean to suppose something to be true without evidence.
(iv) Another word that can replace 'despised' is 'detested'. Both words signify a strong feeling of dislike or hatred.