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