Read the assertion and reason carefully to mark the correct option in question.

Assertion: Pili and fimbriae are known to help the bacteria to become motile in streams.

Reasons: Unlike flagella, pili and fimbriae are surface structures of bacteria.

1. If both assertion and reason are false.

2. If assertion is true but the reason is false.

3. If both assertion and reason are true and the reason is the correct explanation of the assertion.

4. If both assertion and reason are true but the reason is not the correct explanation of the assertion.

The correct option is A If both assertion and reason are false.
Assertion

Pili and fimbriae are known to help the bacteria to become motile in streams.

Elaboration:

Pili and fimbriae are proteinaceous cell surface appendages that emerge from the plasma membrane of many bacteria.

Fimbriae helps in attachment of the bacteria to host surface to help them colonise. Pili are structures that are involved in conjugation process in bacteria. These structures don't help in locomotion.

Reasons

Unlike flagella, pili and fimbriae are surface structures of bacteria.

Elaboration:

Pili and fimbriae are the surface structures of bacteria same as flagella. These structures are also extensions emerging out of the cell wall of bacteria.

Final answer: d. If both assertion and reason are false.