Microsporangia develops in to
Pollens
Sporangia
Megagametes
Pollen sacs
Pollen grains are generally _________ in outline measuring _________ micrometers in diameter.
During meiosis in pollen mother cell the daughter cells are interconnected by passages. The whole structure is called
$A$ : Restitutional nucleus can be observed in endothecium cells.
$R$ : Endothecium cells are usually triploid.
$A$ typical angiosperm anther is _________ and _________.
Which one of the following is resistant to enzyme action?