Final answer:
The themes that 'violence leads to more violence' and 'alcohol can alter one's personality and cause downfall' best describe the complex nature of a narrative, delving into the darker aspects of human experience and the cycle of negative consequences from personal choices.
Step-by-step explanation:
When determining which two statements best describe the main themes of a story, it's important to consider the narrative's depth and complexity. The idea that violence leads to more violence and can have deadly consequences (option d) is a theme that echoes throughout many stories, as it reflects the cycle of aggression and its escalating nature. Moreover, the theme that alcohol can dramatically alter one's personality and cause one's downfall (option f) is widely acknowledged in literature, showcasing the detrimental effects of substance abuse on individuals and their surroundings.
These themes are not just superficial messages; they represent significant explorations into human behavior and societal issues. Literature often delves into the complexities of human nature, morality, and the repercussions of personal choices, which is captured by these two selected themes. Therefore, options d and f offer a nuanced portrayal of the potential areas a narrative might explore in reflecting the darker sides of human existence and the consequences of surrendering to one's vices.