Answer:
The quote from Mark Twain that has a serious tone is:
“Courage is resistance to fear, mastery of fear, not absence of fear."
Explanation:
“Courage is resistance to fear, mastery of fear, not absence of fear" is a serious quote. Twain is honestly explaining what he thinks of courage and fear, of their connection. His opinion is that being brave does not necessarily mean being fearless, but moving ahead in spite of fear.
However, when we take a look at the other quotes, we realize they were written in a humorous manner. Speaking of a summer as if it were winter, playing with the meanings of mind and matter, and advising someone to distort facts are all unexpected and funny topics, none of which can be taken seriously.
