Which of the following is the world's most problematic aquatic weed?

Give differences: Male gametophytic stage and Female gametophytic stage.

Identify the haploid and diploid structures from the following list:
$I$ - Megaspore mother cell
$II$ - Microspore mother cell
$III$ - Egg cell
$IV$ - Male gamete
$V$ - Synergid
$VI$ - Embryo
$VII$ - Antipodal cell
$VIII$ - Zygote
$IX$ - Megaspore
$X$ - Microspore
Select the correct grouping for Haploid and Diploid structures.

Match the items in Column-$I$ with those in Column-$II$ and select the correct option:

Column-$I$	Column-$II$
$(1)$ Pollination by water	$(a)$ Grass
$(2)$ Pollination by wind	$(b)$ Free-nuclear endosperm
$(3)$ Coconut water	$(c)$ Guava
$(4)$ Fleshy fruit	$(d)$ Hydrilla

Which of the following plants produce seeds and possess a pollen tube?

Given below are two statements: One is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$: Both wind and water pollinated flowers are not very colourful and do not produce nectar.
Reason $(R)$: The flowers produce an enormous amount of pollen grains in wind and water pollinated flowers.
In the light of the above statements,choose the correct answer from the options given below: