Answer:
They move by means of flagella.
Step-by-step explanation:
In the given question, the general characteristic of a cell has been discussed in which the one characteristic is not general and is present in the unique cell depending on the structure they are present and function they have to perform.
That exceptional characteristic of the cell is that the cell possesses the flagella which are not a general character as the flagella are not present in all the cells but in few like the sperms.
Thus, They move by means of flagella is correct.