Question

Holdfast, stipe and frond constitute the plant body in case of __________.
A) Rhodophyceae
B) Chlorophyceae
C) Phaeophyceae
D) All of these

Answer 1

Hint: A root-like structure that holds sessile creatures to the seabed is known as holdfast. Stipe is also known as caudicle. It is a small stalk that holds the flower’s ovary in place. Fronds are leaf-like structures. All these structures are part of the plant body belonging to the class of brown algae.

Complete explanation
Option A Rhodophyceae: Red algae belong to the class Rhodophyceae. The brown color of the algae is due to the presence of the pigment−phycoerythrin. The plant body is filamentous and feather-like. These algae do not constitute holdfast, stipe and frond in their plant body.
Option A is not correct.
Option B Chlorophyceae: The class Chlorophyceae consists of green algae. They are present in different shapes. The pigment present in the plant body is chlorophyll. The plant body of these algae are not made up of holdfast, stipe and fronds.
Option B is not correct.
Option C Phaeophyceae: Brown algae belongs to the class Phaeophyceae. The color of the plant body is due to the pigment− fucoxanthin. Fronds, stipe and holdfast are present in the plant body of these algae.
So, option C is correct.
Option D All of these: Holdfast, stipe and fronds are found only in the class Phaeophyceae.
Option D is not correct.

Hence, Option C is the correct answer.

Note:
Among the members of the Phaeophyceae class, the plant body is usually linked to the ground by a holdfast, has stipe which is stalk-like and has fronds which act as photosynthetic structure. Brown algae is multicellular and immobile. These algae are found mostly in marine water.