In angiosperm, all $4$ microspores of tetrad are covered by a layer which is formed by

Functional megaspore in an angiosperm develops into an

A schematic illustration of the pollen grain is called

Nuclear polyembryony is found in

The diagram below shows a fertilised ovule and carpelWhich numbers represent the structures which will become

$(i)$ The future embryo

$(ii)$ The future testa

$(iii)$ The future micropyle of the seeds

$(i) (ii) (iii) $ respectively