Hydrocolloid carrageen is obtained from:

Write a note on Phaeophyceae.

Match the following classes of algae with their characteristic colours:
$A.$ Cyanophyceae $a.$ Green colour
$B.$ Chlorophyceae $b.$ Blue-green colour
$C.$ Phaeophyceae $c.$ Red colour
$D.$ Rhodophyceae $d.$ Brown colour

What is a coenobium?

Which of the following is a method of vegetative reproduction in algae?

The cell wall of algae is composed of which of the following?