It might be stated that his reliability might be compromised because he writes the story many years later and his memories may be skewed. he is the narrator and the protagonist of the story and it is written in first person so he retells what he remembers from his life experience since he was a child.
Answer;
-A motor protein called dynein
Cilia and flagella bend because of a motor protein called dynein.
Explanation;
-Both prokaryotic and eukaryotic cells contain structures known as cilia and flagella. These extensions from the cell surface aid in cell movement. They also help to move substances around cells and direct the flow of substances along tracts.
-Cilia and flagella are formed from specialized groupings of microtubules called basal bodies. If the protrusions are short and numerous they are termed cilia. If they are longer and less numerous they are termed flagella.
A mutation could do that.