1. In somatic cell division it involves diploid cells while in reproductive cell division it involves haploid cells. Somatic cell division involves body formation while reproductive cell division involves reproduction. The importance of somatic cell division is for organisms to grow and repair cells. The importance of reproductive cell division is for offsprings to obtain their genes from their parents. If these two do not occur, it could lead to cancer.
2. The significance of interphase is the replication of the chromosomes and preparation for cell division. In interphase the cell also grows. The most important part of interphase is the S phase where the DNA is completely copied.