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