Answer:
I imagine the answer would be Charles Darwin's theory of natural selection.
Explanation:
Natural selection explains that some organisms, like animals, possess inheritable traits that allow them to better survive within and adapt to their environment, compared to other organisms. That species will be able to outlive those without the trait(s) as they have more opportunities to reproduce and pass their inherited genes onto the next generation. This is why "natural selection" most fits within question number 3's blank space.
