The ability to pass on genes is defined by which of the following?

Explanation

The correct answer is reproductive fitness. Biological fitness specifically refers to an organism's ability to survive and reproduce, thereby passing its genetic material to the next generation. It is a central concept in evolution, indicating how well an organism is adapted to its environment. Differential reproduction involves variation in reproductive success but does not define fitness itself. Evolution is a broad process that includes various mechanisms of genetic change over time, not a specific measure of reproductive success. Natural selection is a mechanism that influences which organisms are more likely to reproduce based on advantageous traits, but it does not directly define the ability to pass on genes.