What is correct for water hyacinth $(Eichhornia \text{ } crassipes)$?
$1.$ Aquatic weed
$2.$ Terrestrial weed
$3.$ Threat to native species
$4.$ Useful to native species
$5.$ Asexual reproduction

In angiosperms,when pollen grains influence the endosperm,what is it called?

$A$ plant with both male and female flowers borne on it is called:

Describe the post-fertilization changes in a flower.

Study the following statements and choose the correct option.
$I-$ Tapetum nourishes the developing pollen grains.
$II-$ Hilum represents the junction between ovule and funicle.
$III-$ In aquatic plants such as water hyacinth and water lily,pollination is by water.
$IV-$ The primary endosperm nucleus is triploid.

Choose the correct option regarding gametes.