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