Answer:
The theory of evolution is a scientific explanation for how species of living organisms have changed and diversified over time. The theory states that all living things on Earth share a common ancestor, and that the diversity of life that we see today is the result of gradual changes that occurred over millions of years. One of the key mechanisms driving evolution is natural selection. Natural selection is a process by which certain traits become more or less common in a population based on how well they help individuals survive and reproduce. This process is driven by three key factors: mutation, variation, and adaptation. Mutation refers to a change in an organism's DNA sequence. Mutations can occur randomly and can either be beneficial, harmful, or have no effect on the organism's survival or reproduction. Variation refers to differences in traits between individuals in a population. Variation can arise through genetic mutations or through the reshuffling of genes that occurs during sexual reproduction. Natural selection acts on this variation, favoring individuals with traits that are better suited to their environment. Adaptation refers to the process by which organisms become better suited to their environment over time. Adaptations can be physical or behavioral, and are the result of natural selection acting on variation within a population.