A tardigrade survives in a dry tun. What can allow activity to return?

• Sunlight returns while the animal remains dry.
• Water returns and rehydrates the surviving animal.
• Air returns while its body remains dried out.

Which change marks drying-induced cryptobiosis in a drying-tolerant tardigrade?

• Forming a dry tun as metabolism becomes very low.
• Remaining active while body water is lost.
• Forming a dry tun while metabolism speeds up.

What does an enzyme do in a cell?

• It speeds up chemical reactions within cells.
• It carries oxygen between the body's tissues.
• It forms the outer boundary around each cell.

What helps Antarctic icefish limit ice growth in their blood?

• Antifreeze proteins heat the blood and melt ice crystals.
• Antifreeze proteins attach to ice crystals and limit growth.
• Antifreeze proteins dissolve ice crystals into the blood.

A deep-sea fish regulates a gas-filled swim bladder. Which claim does this example disprove?

• Some deep-sea fish contain gas-filled bladders.
• Gas-filled bladders change volume with pressure.
• Deep-sea animals lack gas-filled spaces.

Why can pressure adaptations in enzymes matter to deep-sea animals?

• Pressure affects gas spaces, not enzyme activity.
• Pressure changes enzyme shape but leaves activity unchanged.
• Pressure can alter an enzyme's shape and activity.

Using rounded pressures of 1 atmosphere at the surface and 400 at depth, the deep pressure is how many times as high?

Using rounded pressures of 400 atmospheres at depth and 1 at the surface, what is the increase in atmospheres?

A microbe grows well in hot water. Does this prove it also grows well in very salty water?

• Heat tolerance establishes salt tolerance.
• Salt tolerance needs a separate growth test.
• Heat tolerance prevents high salt tolerance.

What do icefish antifreeze proteins and wood frog glucose protection have in common?

• Both reduce freezing damage to cells.
• Both prevent ice from forming in body fluids.
• Both melt body ice by releasing stored heat.