Final answer:
Leiningen chooses to confront the ants due to his confidence in overcoming nature with intelligence, a sense of responsibility, and an unyielding spirit.
Step-by-step explanation:
The character Leiningen from the story 'Leiningen Versus the Ants' by Carl Stephenson is a testament to human determination and ingenuity in the face of overwhelming natural adversity. Leiningen decides to stay and confront the ants because of his confidence in human intelligence over nature, his sense of responsibility towards his land and the people who live and work on it, and his refusal to be defeated by what he perceives as a lesser force.
Despite the dangers posed by the ant swarm, Leiningen is driven by the belief that with careful planning and strategy, he can overcome the seemingly insurmountable threat. His decision is a reflection of his character's perseverance and leadership.