Question

Which group of organisms is represented by the given figure?

A. Diatoms
B. Dinoflagellates
C. Bacteria
D. Euglenoids

Answer 1

In the provided figure, two flagella can be observed. One is lying longitudinally whereas the other is present transversely inside a furrow in between the wall plates.

Complete answer:
Dinoflagellates are marine eukaryotes. These are the unicellular organisms. They are characterized by dinokont flagellation means the two flagella arising from the ventral side of the cell. Moreover, the flagella arising are dissimilar. One flagella is ribbon like and is located transversely while the other is located longitudinally beating posteriorly. Dinoflagellates are known to accumulate over the water surface causing shellfish poisoning. Also, the dinoflagellates possess the property of emitting blue green light which is known as bioluminescence.
On the other hand, diatoms are mostly non-motile while bacteria can have one flagella (monotrichous) or it may have one flagellum at each end (amphitrichous) or numerous flagella can be present as a tuft (lophotrichous) or flagella can be found distributed all over its body except the pole (peritrichous). Furthermore, Euglenoids possess two flagella which are rooted in the cell at the front as basal bodies.

Hence, the correct answer is option (B).

Note: The dinoflagellates belong to the phylum Dinoflagellata. These are single celled eukaryotic organisms. They are generally considered as algae. Most of the dinoflagellates are marine planktons but some can also thrive in freshwater habitats. Environmental factors like salinity, temperature or depth of the sea determines the distribution of population over the sea surface.