Long thin hair-like appendages, like shown above, can be found in many types of bacteria. what are these called?
a. cilia
b. cocci
c. tails
d. flagella

A. cilia

Cilia are those hair-like structures protruding within a cell structure.

In another, 
A flagella (or flagellum plural) is a long strand like structure that is located in the front end part (more like a tail in front). It flips to the left and right in order for the organism to move. It is connected to the reservoir, which contains the storage of food for the organism. 

Answer a bell shaped curve;