Question

The most advanced forms of algae are
(a) Brown algae of Phaeophyceae
(b) Red algae of Rhodophyceae
(c) Yellow algae of Xanthophyceae
(d) Green algae of Chlorophyceae

Answer 1

Algae are chlorophyll- bearing, simple plants with thalloid body structure. There are many groups of algae divided on the basis of their dominant color and reserve food material. The most advanced form of algae has pigments chlorophyll- a and b in dominance.

Complete Step by Step Answer:
The most advanced form of algae is the green algae of Chlorophyceae. The reasons for them being the most advanced group is as follows:
- They are green in color cue to chlorophyll-a and b, thus can exhibit photosynthesis to the maximum efficiency.
- They store their reserve food material as starch inside the plastids. This starch is stored in storage bodies known as pyrenoids.
- It is a diverse group having many varying forms from freshwater to saltwater.
- And the most important reason for them being the most advanced group of algae is the presence of multiple chloroplasts in a single cell.

So, the correct option is ‘Green algae of Chlorophyceae’.

Additional information: Let us learn about the other groups of algae mentioned in the options.
- Brown algae of Phaeophyceae: These are algae having chlorophyll a,c and fucoxanthin. Reserve food material in them is mannitol and laminarin.
- Red algae of Rhodophyceae: These are algae having chlorophyll a,d and phycoerythrin. Reserve food material in them is floridean starch.
- Yellow algae of Xanthophyceae: These algae contain chlorophyll a,c and diadinoxanthin. They are the closest relatives to brown algae.

Note:
- Pyrenoids contain a protein core around which the starch gets accumulated and stored.
- Algae are responsible for half of the total carbon dioxide fixation on Earth.
- Chlorella is a unicellular green alga that is used as a food supplement by space travelers because of its high protein content.