Q 01/05

Which soft-bodied invertebrate has three hearts, bluish copper-based blood and two-thirds of its neurons in its arms?

A) Octopus

B) Lobster

C) Brittle star

D) Sea slug

Answer · why

A) Octopus

Octopus blood is blue because it carries oxygen with hemocyanin rather than iron-rich hemoglobin. One main heart serves the body while two smaller one...

Q 02/05

Which Antarctic deep-sea animal, weighing about 1,000 pounds, is the heaviest living invertebrate known to science?

A) Giant squid

B) Giant tube worm

C) Colossal squid

D) Giant isopod

Answer · why

C) Colossal squid

The colossal squid also has the largest eyes documented in the animal kingdom, 27 to 30 cm across. The heaviest confirmed specimen weighed 495 kg.

Q 03/05

Which microscopic eight-legged invertebrates can dry into a dormant state and survive the vacuum of outer space?

A) House dust mites

B) Tardigrades

C) Water fleas

D) Springtails

Answer · why

B) Tardigrades

Tardigrades, nicknamed water bears, pull in their legs and shrivel into a lifeless-looking form called a tun. In that state they have endured vacuum, ...

Q 04/05

Which armored sea creature has bright blue blood that drug makers use to test injectable medicines for bacterial toxins?

A) Alaskan king crab

B) Blue crab

C) Hermit crab

D) Horseshoe crab

Answer · why

D) Horseshoe crab

The horseshoe crab is no true crab but a closer relative of spiders. Cells in its copper-based blood clot around bacterial toxins, which makes it a se...

Q 05/05

Which spiny-skinned sea animal can regrow lost arms and feeds by pushing its stomach outside its body onto prey?

A) Cuttlefish

B) Brittle star

C) Starfish

D) Feather star

Answer · why

C) Starfish

Starfish pry a clam's shell open a crack, then slip their stomach inside to digest the soft tissue. In some species a single severed arm can regrow a ...