Question

why was natural selection an important contribution to the theory of evolution?
it proved that evolution is true.
it explained how evolution works.
it summarized the process of evolution.
it highlighted the main points of evolution.

Explanation:

Natural selection provided a testable, mechanistic account of how heritable traits that improve survival and reproduction become more common in populations over generations, filling a critical gap in early evolutionary thought by explaining how evolution occurs, rather than just stating that it does or summarizing its outcomes.

Answer:

It explained how evolution works.