Hair-like projections used by bacilli and spirilla to move themselves are called cilia or:

• A. fimbriae
• B. flagella
• C. axial filaments
• D. pili

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the question is asking about the structures that enable movement in bacilli and spirilla bacteria.
2. Step 2: Recall that cilia are hair-like projections used for movement in eukaryotic cells, but bacteria do not have cilia.
3. Step 3: Identify the bacterial structures listed: fimbriae, flagella, axial filaments, and pili, and know their functions.
4. Step 4: Recognize that fimbriae and pili are primarily used for attachment and conjugation, not movement.
5. Step 5: Know that flagella and axial filaments are involved in bacterial motility, with flagella being the common structure for movement in bacilli and spirilla.