Natural selection is best described as?

Natural selection is a fundamental mechanism of evolution that describes how certain traits become more or less common in a population based on the individuals' ability to survive and reproduce in their specific environment. The correct choice articulates this concept effectively by stating that organisms that are better adapted to their environment tend to survive and reproduce more successfully than those that are not as well adapted.

This adaptability can involve various traits, such as physical characteristics, behaviors, or physiological processes that enhance survival and reproductive success under specific environmental conditions. Over generations, these advantageous traits become more prevalent within the population, leading to evolutionary changes.

The other options do touch on aspects of evolution or population dynamics, but they do not encapsulate the essence of natural selection as clearly as the correct choice. For instance, the notion of “survival of the fittest” captures a part of natural selection but does not fully explain the reproductive aspect involved. Random variation of traits underlines the variation aspect of evolution, yet it is the non-random nature of survival and reproduction that defines natural selection. Lastly, while the development of new traits can occur, it is not the central principle of natural selection; instead, natural selection operates on existing variations in a population.