Pollen grains of many species cause severe allergies and bronchial afflictions in some people,often leading to chronic respiratory disorders such as .....

What is a $Pollen-embryo$?

Which one of the following statements is correct?

Sperm cells of angiosperms differ from the rest of the plant groups like gymnosperms by

Draw a chart of the life cycle in angiosperms.

An angiospermic male plant with $24$ chromosomes in its pollen mother cells is crossed with a female plant bearing $24$ chromosomes in its root cells. What would be the ploidy of the embryo and endosperm respectively formed after this cross?