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