What is the stored food material in algae?

If you are asked to classify different algae into distinct groups,which of the following characteristics would you choose?

Assertion $(A)$: Algae are known as primitive plants.
Reason $(R)$: The body structure of algae is simple.

Which of the following statements are applicable to brown algae?
$(I)$ They contain pigments like chlorophyll $a$,chlorophyll $c$,carotenoids,and xanthophylls.
$(II)$ They vary in color from olive green to various shades of brown.
$(III)$ Food is stored as complex carbohydrates,in the form of laminarin or mannitol.
$(IV)$ The cell wall is composed of cellulose and algin.
$(V)$ The cell wall is covered on the outside by a gelatinous coating of algin.

Which of the following produces isogamous and non-flagellated gametes?

Cilia and flagella are absent in the life cycle of . . . . . . .