For a gene, if $AA = \text{male plant}$ and $BB = \text{female plant}$, find out the genotype of the endosperm and the embryo.

In multicellular organisms, life begins with a .......... .

In anther culture,some diploid plants were reported along with haploids. They have evolved from:

Which of the following cells of the embryo sac degenerate after fertilisation in angiosperms?

In which of the following organisms does the zygote undergo meiosis?

Study the following statements.
$I$. Pollen grains of many species cause severe allergies and bronchial afflictions in some people,often leading to chronic respiratory disorders.
$II$. Pollen grains are rich in nutrients.
$III$. Carrot grass came into India as a contaminant with imported wheat.