Traditionally, doctors use gestational age, the number of weeks from fertilization to birth, to determine whether a preemie should receive invasive care.
4 Turbellarians are monoecious with the reproductive systems adapted for internal fertilization. And the monogenetic flukes (class Monogenea) are mostly ectoparasites of fishes.
A long-term field experiment was carried out to study the effect of fertilization on the organo-mineral complexation and the combined forms of humus of phaeozem in Jilin Province, China.