How does asexual reproduction occur in $Spirogyra$?

Agar is commercially obtained from $..........$.

Identify the organism shown in the given figure.

What is the stored food (nutrient) in algae?

Which of the following statements are true regarding the figure given below?
$(i)$ It shows oogamy and post-fertilization development.
$(ii)$ Male gamete is small and motile.
$(iii)$ Stored food is floridean starch.
$(iv)$ Pectin,cellulose,and polysulphate esters are present in the cell wall.

Match Column $I$ with Column $II$ and choose the correct option:

Column $I$	Column $II$
$a.$ Shallowest depth	$(i)$ Green algae
$b.$ Intermediate depth	$(ii)$ Brown algae
$c.$ Greatest depth	$(iii)$ Red algae