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