Q 01/05

Which metal, carried in the protein hemocyanin, turns the blood of squid and lobsters blue instead of red?

A) Iron

B) Copper

C) Cobalt

D) Zinc

Answer · why

B) Copper

Copper does the job that iron does in human blood, binding oxygen and turning blue as it does so. The same pigment runs through snails, spiders and sc...

Q 02/05

Which microscopic drifting organisms make about half of Earth's oxygen by photosynthesis in the sunlit sea?

A) Zooplankton

B) Foraminiferans

C) Phytoplankton

D) Siphonophores

Answer · why

C) Phytoplankton

Phytoplankton manage it while making up only about 1% of the planet's plant biomass. They also sit at the base of nearly every food chain in the sea.

Q 03/05

In which fish does the male carry the eggs in a brood pouch until the young are born?

A) Seahorse

B) Lionfish

C) Pufferfish

D) Boxfish

Answer · why

A) Seahorse

Seahorse fathers receive up to 1,500 eggs from the female and carry them for 9 to 45 days. The young emerge fully formed but very small.

Q 04/05

Which marine mammal has no blubber and relies instead on the densest fur of any animal to stay warm?

A) Harbor seal

B) Sea otter

C) Walrus

D) Polar bear

Answer · why

B) Sea otter

Sea otter fur packs up to 150,000 hairs into each square centimetre. The animal grooms constantly, because the coat only keeps water out while it stay...

Q 05/05

Which bright reef fish rasps algae off coral rock and excretes the remains as sand?

A) Triggerfish

B) Surgeonfish

C) Butterflyfish

D) Parrotfish

Answer · why

D) Parrotfish

Parrotfish digest the edible part and pass the rest as sand, which helps to build beaches and small islands.