Nose
Spine
Feet
Mouth
Other sea urchins
Small fish
Sea cucumbers
Algae
Both intertidal area and subtidal areas
On the beach
Subtidal area only
Intertidal area only
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
Echinoderms
Strongylocentrotus
Animalia
Purpuratus
Toothpick
Dome
Pentamerous
Porcupine