What inherent characteristics of populations did both Darwin and Wallace propose were need for natural selection to lead to adaptation?

Darwin and Wallace both the naturalist known for the theory of natural selection. These naturalist have proposed various inherent characteristics that are essential for natural selection process to result in the change or adaption according the atmosphere.

The inherent characteristic is that the population must have variability as trait, increasing the competition by over reproduction and in a population some individuals are successful at reproduction.

Thus, the correct answer is mention above.