Ulothrix and Spirogyra  both have multicellular filamentous thallus organisation.

Yes, this is correct answer. Chara and Aulosira are larivicidal algae. They do not allow mosquito larva to grow.

Laminaria is a genus of several species of brown algae, all sharing the common name kelp. Fucus is a genus of brown algae found in the intertidal zones of rocky seashores almost throughout the world.

Red colour of members of Rhodophyceae is due to presence of phycoerythrin. Phycocyanin is a pigment found in blue green algae.

Yes, this is the correct answer. Algae like Chlorella and Synechococcus are used in long distance space travels. These have rapid rate of photosynthesis and are thus able to utilise all the CO₂ released by astronauts and provide oxygen and food required by the travellers.

Researches in genetics and cytology are carried out on Acetabularia.

Oedogonium species are typically epiphytic and attached to aquatic vegetation or inorganic substratum by a basal holdfast cell. Nostoc is a species of endophytic algae that occurs in the thallus of Anthoceros. Oscillatoria is a species of epizoic algae living on bodies of turtles. Zoochlorella is a species of endozoic algae living in the body of Hydra.

Laminaria is used as surgical tool in the opening of wound due to its gentle swelling property.

Certain algae like Macrocystis, Laminaria, Ascophyllum, Lessonia are used for alginates extraction.

Chlamydomonas, Scenedesmus, Chlorella, Pondorhina, Euridina, etc., are living in sewage water. They are mainly useful to clean the water by releasing oxygen.

Spirulina, filamentous blue-green algae, is cultivated around the world and used as a human dietary supplement, as well as a whole food.

Laminaria is a rich source of iodine. Polysiphonia is a rich source of bromine.

Pandoria reproduce sexually through anisogamous mode.

Bromine is obtained from red algae like Rhodomela and Polysiphonia.

Agar agar is a product obtained from numerous algae, mainly of the genus Gracilaria, Gelidium and Eucheuma. Algin strongly is produced commercially from a variety of species of Laminaria. Funori is a polysaccharide extracted from the mucilage of Gloiopeltis Furcata, G. Complanata and G. Tenax.