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