The short extensions of the cell wall shown in the picture are called a) pili. b) cilia. c) flagella. d) conjugation tubes.

The right answer is A) pili

Pilus (plural pili) is an extension of a protein located on the surface of the wall of many Gram-negative bacteria (and exceptionally Gram-positive bacteria), shorter and finer than flagella, they can not be involved in mobility. They are divided into two categories: the common pili and the sexual pili (which, despite this name, have nothing to do with reproduction, but rather with transmission and its coding).

Cilia is a wrong answer because the point of insertion of eyelashes and flagella is in the cytoplasm, in contact with the plasma membrane. So these are not extensions of the bacterial wall.

c. heat from the poles back down towards the equator.