Final answer:
The correct pronoun for the sentence 'Despite the rain, Mark and (he, him) still went for a run' is 'he' because it is part of the compound subject 'Mark and he' and therefore should be in the subjective case.
Step-by-step explanation:
The correct pronoun to use in the sentence 'Despite the rain, Mark and (he, him) still went for a run' is he. This is because pronouns that function as subjects of a sentence should be in the subjective case. In this sentence, 'Mark and he' form a compound subject for the verb 'went,' hence the subjective case pronoun 'he' is used.
Pronouns have three cases: subjective, objective, and possessive. When pronouns are subjects, like in the sentence 'Antonio and I have occasional disagreements about the dishes.', we use subjective case pronouns such as 'I'.
When pronouns are objects, as in 'Disagreements come up between Antonio and me.', we use objective case pronouns such as 'me'. Lastly, possessive case pronouns show ownership, for instance, 'The notes are his and mine.'