Human sperm vs. the sperm whale - Aatish Bhatia

What happens when a bacterium is pushed and then released in water?

• It continues to glide for a long distance.

• It stops almost immediately, traveling less than an atom's width.

• It changes direction and swims away.

• It floats to the surface.

Which factors are used to calculate the Reynolds number, which helps predict how a fluid will behave around a moving object?

• Temperature, pressure, and color of the fluid.

• Size of the swimmer, its speed, the fluid's density, and its viscosity.

• The swimmer's age, weight, and the fluid's volume.

• The amount of light, sound, and heat in the fluid.

How do single-celled organisms like Paramecia manage to move through water?

• They use grappling hooks to pull themselves forward.

• They release chemicals to thin the water around them.

• They deform their paddles to create more drag on the power stroke.

• They spin their tails like a corkscrew.

How does the bacterium H. pylori move through the thick, acidic mucus in our stomachs?

• It swims by flapping its tail rapidly.

• It uses tiny legs to walk across the mucus.

• It releases a chemical to thin the surrounding mucus.

• It waits for the mucus to naturally thin out.