It seems that you missed the given choices of the question above which are the following:
A. the past is not something we can talk about.
B. there are no words to convey the pain of the past.
C. The battle of the sexes will go on forever.<span>
D. Men’s and women’s roles are deeply rooted in our species.
Anyway, the correct answer for the given question above would be option D. When the </span><span>author says in lines 40–41 that “I'm convinced the past, we must contend with is deeper even than speech,” he means that </span>Men’s and women’s roles are deeply rooted in our species. Hope this answer helps.
Both fish and whales swim and live in the ocean.
The phrase from this passage which demonstrates that the author is identifying a source of debate is C. "the controversy stems from..."
To stem from something means to originate from, so this would be the logical answer.