Final answer:
Nietzsche believed that self-depreciating humor is essential to the survival of mankind and that the human condition should be approached with irony.
Step-by-step explanation:
Nietzsche believed in several ideas related to humor and the human condition. First, he did not believe that self-depreciating humor was tantamount to self-destruction, as option (1) suggests. Instead, he believed that self-depreciating humor is essential to the survival of mankind, as it allows individuals to confront their own weaknesses and learn from them. Additionally, Nietzsche believed that the human condition should be approached with irony, as stated in option (3). Finally, he did not believe that humor related to existence has not been apparent, as option (4) suggests. Rather, he believed that lightness and wisdom will eventually be united, as stated in option (5).