And, but and so

Both snails ___________ hermit crabs use shells to protect themselves.

• and

• but

• so

A snail has a shell of its own ___________ a hermit crab does not.

• and

• BUT

• SO

When there is danger, tortoises ___________ snails hide inside their shells.

• and

• but

• so

Clams have muscles ___________ they can open and shut their shells.

• and

• but

• so

Lobsters move by walking slowly on the sea floor ___________ swim backwards when they flee.

• and

• but

• so