Final answer:
The main cause for genetic variation within families, society, and life in general is mutation and sexual reproduction. Mutation, a permanent change in DNA sequence, is the ultimate source of new genetic variation in any population. Sexual reproduction also leads to genetic diversity as unique combinations of alleles assemble to produce unique genotypes and phenotypes in each offspring.
Step-by-step explanation:
The main cause for genetic variation within families, society, and life in general is mutation and sexual reproduction. Mutation, a permanent change in DNA sequence, is the ultimate source of new genetic variation in any population. When individuals have a mutated gene, it can result in different traits than other individuals in the population. Sexual reproduction also leads to genetic diversity as unique combinations of alleles assemble to produce unique genotypes and phenotypes in each offspring.