Question

Whirling whips are protists which possess two flagella that beat
(a) Slightly towards one side so as to cause rotation of the organism while moving forward
(b) Forward, backward, and sideways depending upon the requirement
(c) At right angles to each other due to being present in different grooves
(d) Along with numerous cilia

Answer 1

Hint: Whirling means a rapid movement while revolving or moving round and round. This movement is due to the strategic position of the two flagella. Whips is a term associated with the slender and long flagellum.

Complete answer:
Dinoflagellates are flagellated. They exhibit a heterokont type of flagellation. In such a type of flagellation, the two flagella beat in the opposite direction while occupying different positions. One is known as the transverse flagella while another is known as longitudinal flagella. They both are located at right angles to each other due to being present in different grooves. The beating of these two dissimilar flagella has given them the name ‘whirling whips’.
Kingdom Protista is divided into three classes - Photosynthetic protists, Consumer-decomposer protists (slime moulds) and Protozoan protists. Dinoflagellates are photosynthetic protists. They represent one of the main groups of phytoplankton. Phytoplanktons are any green photosynthetic organisms which may be passively drifted through the water current. These include bacteria, dinoflagellates, diatoms and algae. Some characteristic features of dinoflagellates are as follows:
Habitat: Most of them are marine but some can be found in freshwater.
Structure: They are basically unicellular. Cells are covered by a rigid coat of well-articulated and sculptured plates made up of cellulose. This is the reason they are also known as armoured dinoflagellates.
Flagellation: The longitudinal flagella originates from a groove in the centre of its body and ends at its deep posterior part. It runs through the sulcus or ridges that are present between their armour of cellulosic plates. Its movement propels dinoflagellates in the forward direction. The transverse flagella are ribbonlike and a little flattened. It occupies a cingulum - a groove in the middle plane of their body which divides it into two equal upper and lower halves. It encircles the whole body. Its beating helps the organism to turn its body while moving forward. The coordinated movement of both the flagella helps in the locomotion and easy gliding through the waters
So, the correct answer is ‘At right angles to each other due to being present in different grooves.’.

Note: Mesokaryon is composed of ‘meso’ and ‘karyon’ which means ‘middle’ and ‘nucleus’ respectively. It is a special type of nucleus found only in dinoflagellates which consist of condensed chromosomes. Dodger gave the term ‘mesokaryon’ to the nucleus of dinoflagellates because they exhibit the characters of both prokaryotic as well as the eukaryotic nucleus. The nucleus of dinoflagellates is well organised like that of eukaryotes but the nuclear division process resembles that of prokaryotes.