Can someone plz help me! :(

If one writes logically, he will prove his point. is this sentence correct or contains an unwarranted shift in person?

[he] let his gaze wander to the swirling water of the stream racing madly beneath his feet. a piece of dancing driftwood caught his attention and his eyes followed it down the current. how slowly it appeared to move! what a sluggish stream! what contrasting words are used to describe the stream in this passage?

Which sentence has an incorrect shift in pronoun-antecedent agreement? a) each teacher needs to be paired up. b) each man needs to carry his own load. c) each of these women runs their own business. d) each child should bring his or her own lunch.