Question

The members of Phaeophyceae or brown algae are found primarily in / on:
A. Freshwater
B. Marine habitat
C. Terrestrial habitat
D. Rock

Answer 1

Hint: Brown algae are the common name of Phaeophyceae. Protists means (plant) and phaeophyta means ( brown algae). The brown alga Sargassum ilicifolium was used for the first time isolation of the terpenoid C -27 alcohol 1,1' ,2- trinorsqualenol (1) from marine water.

Complete answer:
It is present in the sea water and attached in the rocks that present in it. Its multicellular function includes about 2000 species. There are 8 main species of brown algae (phaeophyceae) from Madagascar that have been investigated for the purpose of chemical constituents. The crude extract obtained from the all 8 species of the brown algae exhibited a pronounced antimicrobial activity against the gram positive bacteria known as ( streptococcus pneumoniae, staphylococcus aureus and bacillus).
On the basis of size it is also known as kelps. It looks like leaf-like structure examples: Luminaria attached with substratum through the hold fast and the upper body also called stripe and above stripe leafy like structure is present in it. Second example is sargassum and it is a free floating structure and not attached to any surface and moves freely in this stripe and holds fast and is not present. It has giants of protists.
It looks like a thread-like structure and is present in the region of Sargasso sea. And because of long structural body marine ships prohibited to pass that area otherwise it can tackle with the ships. It can sink the ship in the sea. Brown algae is a source of food of marine animals.
 There are two types of reproduction 1) asexual 2) sexual
1) Asexual
> Fuchs :- kind of diploid cell help to produce zoospores
> Ectocarpus :- With the help of unicellular and multicellular produce zoospores that are haploid kinds of plants.

2) Sexual
In this sexual reproduction observed in oogamy and eggs development in the female gametangium part also called as carpogonium.

Therefore the correct option is (B) marine habitat

Note: Seaweeds live in a complex and dynamic location and are increasingly searching for new natural compounds of marine biodiversity. Other economically valuable red algae, such as the producers of the phycocolloids agar, carrageen and germinate to produce both the multicellular gametophyte thalli. Brown algae are found primarily in marine habitats and show great variations in size and form. In the brown algae a large amount of brown pigment (fucoxanthin) is present which is covered with the green color of the chlorophyll pigments. And hemochrome is a non motile portion present in the chlamydomonas spores containing the red pigment.