Xenia is a effect of pollen grains on
Embryo
Endosperm
Embryo sac
Nucellus
In angiosperm, all $4$ microspores of tetrad are covered by a layer which is formed by
Pollination by insects is called
Xenia and metaxenia terms are related with
The role of double fertilization in angiosperms is to produce
When pollen tube enters by integuments, then the process is called