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