Sentence:  By its nature, that is whether it develops with or without fertilization, simple <WSD>polyembryony</WSD> can be sexual or asexual. 
Meaning of the word marked with <WSD> tags:  The production of two or more embryos in one seed, due either to the existence and fertilization of more than one embryonic sac or to the origination of embryos outside of the embryonic sac.