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