Question

Iodine is obtained from
A.Laminaria
B.Polysiphonia
C.Porphyra
D.Chlorella

Answer 1

Hint: Algae are the simple plants that have chlorophyll and are largely aquatic in nature. They are broadly divided into green algae, brown algae and red algae. They are useful for us in many ways. We get food, minerals and many other economically important substances from various forms of algae.

Complete answer:
 Brown algae or phaeophyceae are marine algae as they live in sea water. Laminaria is a brown algae and we obtain Iodine from it.
Brown algae contains photosynthetic pigments like chlorophyll a, chlorophyll c, carotenoids and xanthophylls. Know that giant forms of brown algae are present and are called kelps.
Other than minerals, algae provides several other substances for us. They form the basis of food cycle in almost all aquatic animals as they are the primary producers of energy rich compounds.
They are autotrophic in nature and prepare their own food through photosynthesis. In this process, they fix carbon dioxide. Know that about half of total carbon dioxide fixation is done by these plants.
They also provide us several water holding substances like algin from brown algae and carra green from red algae.
These substances are commonly used in preparation of jellies, ice creams etc.
Agar is another important substance obtained from algae. It is a jelly like product.
Many of the algal species are used as food. Protein rich unicellular algae like Chlorella and Spirulina are widely used as food supplements by astronauts.

Hence the correct answer is OPTION(A)

Note: Gelidium and Gracilaria are the names of algae that provide agar. It is widely used in microbial culture in preparation of media for culture of microorganisms. These algae belong to the group of red algae.