Make and defend a claim based on evidence that inheritable genetic variations may result from: (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and/or (3) mutations caused by environmental factors.

This chapter consists of topics like Variation of Traits - In sexual reproduction, chromosomes can sometimesswap sections during the process of meiosis (celldivision), thereby creating new genetic combinationsand thus more genetic variation. Although DNAreplication is tightly regulated and remarkably accurate,errors do occur and result in mutations, which are alsoa source of genetic variation. Environmental factors canalso cause mutations in genes, and viable mutationsare inherited.Environmental factors also affect expression of traits, and hence affect the probability of occurrences of traits in a population. Thus the variation and distribution of traits observed depends on both genetic and environmental factors. etc.