The sexual reproduction in $Spirogyra$ is:

$A$: Pyrenoids may or may not be surrounded by a sheath of starch plates in algae.
$R$: In higher plants,these are replaced by amyloplasts.

In Hammerling's nucleocytoplasmic experiments,$Acetabularia$ is used,which is a:

Which type of algae is found at the greatest depth in the ocean?

Floridean starch is the reserve food material in which of the following?

Agar-Agar is obtained from