Question

Algae that form motile colonies are:

• A. Nostoc
• B. Volvox
• C. Spirogyra
• D. Chlamydomonas

Answer 1

The correct option is B

Volvox

The correct option is B.

Explanation of correct option:

1. Volvox belongs to the class Chlorophyceae.
2. They are commonly called green algae as the chief pigment in them is chlorophyll A.
3. They form grand spherical colonies of up to 35,000 to 40,000 cells.
4. Volvox bears two flagella, whip-like hairs, and eyespots which help the colony move towards the light.

Explanation of incorrect options:

Option A:

Nostoc is a cyanobacteria, not an alga.

Option C:

Spirogyra forms long, filamentous colonies that are not motile.

Option D:

Chlamydomonas form microscopic unicellular colonies that are not motile.

Final answer: Algae that form motile colonies are Volvox.