1. It is the process which provides the cells required for the growth of i zygote into a functioning multicellular organism this requires an increase in number of cells from one to 6 x 1013 in humans. 2. It supplies the cells to repair worn- out or damaged tissues. In the human the replacement of skin, gut and lung linings and blood cells requires about 1 x 1011 cells per day. 3. It maintains the chromosome number. Daughter cells have identical sets of chromosomes and so function harmoniously as part of the tissue, organ or organism. 4. Asexual reproduction provides offspring which are genetically identical to the parent ideal when rapidly establishing a population Mitosis provides the cells which make up the fragments of the parent body dispersed during this form of reproduction.