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