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