2.  Variations:
a. Biparental - most common
     Dioecious (Gr. Di = two; Oikos = house)
 gonochoristic
b. Parthenogenesis
     (Gr. Parthenos = virgin; genesis = origin)
     Embryos develop from unfertilized eggs -
   may be diploid or haploid!
     Some flatworms, rotifers, crustaceans,
lizards