How do spirochetes and spirilla differ?
A) Spirochetes do not have a cell wall but spirilla do.
B) Spirilla are found in chains of cells whereas spirochetes exist as individual cells.
C) Spirilla have an external flagella but spirochetes have axial filaments.
D) Spirochetes have a rigid, corkscrew shape while spirilla are helical and more flexible.
E) Spirochetes and spirilla are basically the same organisms and the terms can be used interchangeably.
Answer: C