Everything your body does
<span>Gametes are haploid cells that fuses with another haploid cell during fertilization. For human being, the gametes are the egg cells and the sperm cells and human fertilization is the union of a human egg and sperm, which usually occur in the ampulla of the fallopian tube. </span>
Regeneration in planarians depends on the presence of stem cells called neoblasts. These cells are distributed throughout the body and, when part of the worm has been amputated, they are activated to reform the tissues that have been removed.