How many of the following algae belong to the category of red algae?
Polysiphonia,Gelidium,Laminaria,Spirogyra,Porphyra,Fucus,Chlamydomonas,Polytrichum

Read the following statements and identify the characters related to the alga shown in the diagram:
$(a)$ It is a member of Chlorophyceae
$(b)$ Food is stored in the form of starch
$(c)$ It is a monoecious plant showing oogonium and antheridium
$(d)$ Food is stored in the form of laminarin or mannitol
$(e)$ It shows dominance of pigments chlorophyll $a, c$ and Fucoxanthin.
Choose the correct answer from the options given below:

The product of conjugation in $Spirogyra$ or fertilization in $Chlamydomonas$ is .....

Which one is a parasitic algae?

Which type of algae helps in the nitrogen economy?

The cell wall of algae is composed of: