Food is stored as floridean starch in Rhodophyceae. Mannitol is the reserve food material of which group of algae?

$Chlamydomonas$,$Volvox$,$Ulothrix$,$Spirogyra$ and $Chara$ are examples of:

Phycoerythrin is the major pigment in

$100$ zygospores,alternating with empty cells in Spirogyra,are formed under ................. conjugation and the total number of daughter filaments formed will be ..........................

Identify the algae shown in the given diagrams $(a)$,$(b)$,$(c)$,and $(d)$.

In $Ulothrix$,the cell contains