What is the ploidy of the Primary Endosperm Nucleus $(PEN)$ in angiosperms?

Differentiate between the following:
$(i)$ Red algae and brown algae
$(ii)$ Liverworts and moss
$(iii)$ Homosporous and heterosporous pteridophytes
$(iv)$ Syngamy and triple fusion

How many and what type of male gametes are produced by the male gametophyte of $Capsella$?

What is the fate of the male gametes discharged in the synergid?

Double fertilization is essential for the formation of:

Which is the triploid tissue in a fertilised ovule? How is the triploid condition achieved?