Question

Choose the correct statement about the protist given in the diagram below.

• A. These microscopic organisms float passively in water currents and are found in both marine and freshwater environments.
• B. These protists are generally biflagellates, of which one lies longitudinally and the other transversely in a furrow between the wall plates.
• C. These biflagellate protists are autotrophic in the sunlight and heterotrophic in its absence.
• D. Their cell wall has stiff cellulose plates on the outer surface and deposits of such is known as diatomaceous earth.

Answer 1

Answer: (B)

The given diagram is that of a dinoflagellate.
These organisms are mostly marine and photosynthetic. They appear yellow, green, brown, blue or red depending on the main pigments present in their cells. The cell wall has stiff cellulose plates on the outer surface. Most of them have two flagella; one lies longitudinally and the other transversely in a furrow between the wall plates. Very often, red dinoflagellates (Example: Gonyaulax) undergo such rapid multiplication that they make the sea appear red (red tides). Toxins released by such large numbers may even kill other marine animals such as fishes.