Atype of comparison that focuses on one source first and the second source next is known as comparison

Which of these authors wrote a story that revolved around a captains underwater adventures with his crew and a sub marine long before the submarine was actually invented

What is the independent cause in this sentence? "if the poem is about going mad when love is lost, what would happen if love didn't die? "

What did mark twain contribute to the history of the novel? select all that apply.