Why is it important for dna to be replicated before mitosis

DNA replication needs to occur because existing cells divide to produce new ones. It needs to be copied before cell division so each new cell created can receive a new full set of "instructions"

Meiosis is important because it produces haploid sex cells that are used in sexual reproduction. This ensures that the number of chromosomes after fertilization is the normal diploid number of chromosomes for that organism. Meiosis also ensures that genetic differences result among organisms of the same kind.