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