Answer;
Evolution
Mutations such as polyploidy and crossing over provide the genetic basis for evolution.
Explanation;
Evolution is the change in the characteristics or traits of a species over several generations and relies on the process of natural selection.
It occurs when some individuals or some alleles (alternative form of gene) reproduce themselves more than others,increasing their prevalence in subsequent generation.
Polypoidy and crossover brings about mutations that cause changes in characteristics and traits over time resulting to evolution.