Question

bacteria swim by ______.

• constantly changing the electrical charges to pull and repulse
• whipping the flagellum filament back and forth like an oar
• adhering to surfaces and pulling the cell akin to a person climbing a ladder
• spinning the flagellum filament like a propeller

Explanation:

To determine how bacteria swim, we analyze each option:

• The first option about electrical charges is incorrect as bacteria don't use electrical charges for swimming.
• The second option (whipping flagellum like an oar) is wrong because bacterial flagella rotate, not whip back - and - forth like an oar.
• The third option (adhering to surfaces and pulling) describes a type of movement for some bacteria on surfaces, not swimming.
• The fourth option is correct. Bacterial flagella function by spinning the flagellum filament, similar to a propeller, which enables them to swim in liquid environments.

Answer:

D. spinning the flagellum filament like a propeller