Hydrocolloid carrageen is obtained from:

Isogamous condition with non-flagellated gametes is found in

Which of the following shows the absence of chlorophyll $b$?

Maximum number of chloroplasts recorded in Spirogyra is

Select the correct option for the cell wall of green algae.

Read carefully the given statements about algae and choose the correct option.
$I$. The plant body is thalloid.
$II$. Mainly aquatic.
$III$. Reproduction takes place by vegetative,asexual,and sexual methods.
$IV$. Volvox and Ulothrix are the colonial forms of algae.