The element present in thyroxin is obtained from

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

......... is an example of $Phaeophyceae$.

Autotrophic thallophytes are called .........

$A$ : $Fucus$,a brown alga shows oogamy.
$R$ : Female gamete is quite large as compared to the male gamete.

The antibiotic "chlorellin" is extracted from which genus?