Seed habit is linked to
a)	Homospory	b)	Heterospory	c)	Parthenogenesis	d)	Parthenocarpy

(b)

Some of the pteridophytes produce smaller spores called microspores and larger one called megaspore. This nature is called heterospory. In angiosperms there is only one functional megaspore. The male and female gametes fuse to form zygote which eventually developes into embryo. The embryo forms the seed.