Final answer:
New species evolve from pre-existing species by the accumulation of genetic mutations, which lead to different traits that natural selection, genetic drift, or gene flow can act upon, eventually resulting in speciation.The correct answer to the question is 'b) Genetic mutations'.
Step-by-step explanation:
New species evolve from pre-existing species primarily through the accumulation of genetic mutations. These mutations introduce new alleles into a population, which can then be acted upon by natural selection, genetic drift, and gene flow. Natural selection favors traits that confer survival and reproductive advantages, leading to a change in allele frequencies within a population, while genetic drift results from random fluctuations in allele frequencies due to chance events.
Speciation, the formation of new and distinct species in the course of evolution, can occur when populations become reproductively isolated from each other. Mutations can also result when gene duplication events occur, providing the opportunity for new functions to evolve as one gene copy maintains the original function while the other diverges. Evidence for evolution and the ongoing process of speciation is richly documented through fossils, molecular structures like DNA, and the geographical distribution of species.
The correct answer to the question is 'b) Genetic mutations'. These are the fundamental changes that can lead to the evolution of new species over time by creating the hereditary diversity necessary for natural processes like natural selection to act.