<span>Most human communication cannot be understood outside of the context in which it occurs</span>
Well it would depend if you wanted to put a small break there or not.
But yes they are all placed correctly
<span>B) The text structure is problem and solution; the words safest and causing indicate this.</span>
The theme highlighted in the mentioned excerpt would be perseverance.
The excerpt tells of Rainsford's courageous act of braving the sea to go to the direction of the shots despite of the harsh conditions at the sea. This is evidenced by the phrase "he fought the sea".
The term "doggedly" also describes a persistent pursuit which was what Rainsford showed. He showed perseverance in his actions.