Điền từ : swim, tail, shell, arms, shellfish, feet, hard, spines, swim, shell, claws, swim. The crab has a ________. The shell is _________. It has two strong ________. Crabs can ______. The starfish has five _________. It has sharp __________. It has lots of tiny ________. It cannot ________. The fish can ________ quickly. It has a trong _______ and fins. The shellfish lives in its ________. Crabs eat __________.