Small fish
Algae
Other sea urchins
Sea cucumbers
Spine
Nose
Feet
Mouth
Intertidal area only
On the beach
Both intertidal area and subtidal areas
Subtidal area only
Because a sea urchin's egg is relatively big
Because the eggs make great omlettes
Because sea urchins have large numbers of eggs
Because sea urchins have large numbers of relatively big eggs
Toothpick
Porcupine
Pentamerous
Dome
Strongylocentrotus
Echinoderms
Animalia
Purpuratus