flagellum is the answer! Hope this helps!!!!!
B. Subgroups
<span>When constructing a dichotomous key, the first step is to look at the group of objects or organisms and separate them into two groups based on a single distinguishing characteristic. Then continue to separate each of the groups until each object has its own separate set of characteristics.</span>
Because mostly some microorganism may be very small and harmful that can affect humans or animals just by the experience of the microorganism.
